g

S o

^^ P-

= CD

o^

^S r-^

X_i.

= ru

%=

^= o

= a

CD —

^'^

S — '

^ r-q

Sf O

^s m

= a

^

SOCIETY OF AMERICAN BACTERIOLOGISTS

MONOGRAPHS ON SYSTEMATIC
BACTERIOLOGY

Volume I General Systematic Bacteriology
R. E. Buchanan, Iowa State College
597 pages. $6.00, net postpaid

GENERAL
SYSTEMATIC BACTERIOLOGY

<■ -S

MONOGRAPHS ON SYSTEMATIC BACTERIOLOGY

GENERAL
SYSTEMATIC BACTERIOLOGY

History, Nomenclature, Groups of Bacteria

BY

R. E. BUCHANAN, PH.D.

Professor of Bacteriology, Bacteriologist of the Iowa Agricultural Experiment Station

and Dean of the Graduate College, Iowa State College,

Ames, Iowa

\<<-

Kii

BALTIMORE

WILLIAMS & WILKINS COMPANY

1925

Copyright 1925
WILLIAMS & WILKINS COMPANY

Made in United States of America

Published January, 1925

ALL RIGHTS RESERVED

COMPOSED AND PRINTED AT THE

WAVERLY PRESS

By the Williams & Wilkins Company

Baxtimobe, Md., U. S. a.

CONTENTS

Preface 9

I. Classification of the Genera and Higher Groups of Bacteria. Historical,

1773-1922 15

II. Codes of Nomenclature and Their Application in Bacteriology 109

The Rules of Bacterial Nomenclature According to Lehmann and

Neumann 110

The International Code of Botanical Nomenclature 113

The International Code of Zoological Nomenclature 137

The Type Basis Code Suggested by the Committee on Botanical Nomen-
clature of the Botanical Society of America 146

Suggestions and Recommendations of the Society of American Bacteri-
ologists 149

III. Nomenclatural Status of Names Which Have Been Applied to Groups

of Bacteria of Higher Rank than Species. Alphabetically Arranged. . 152

Bibliography 533

Subject Index 561

Author Index 589

^iki"^

PREFACE

The present volume is the first of a series of monographs in the
general field of systematic bacteriology. The data presented have
been collected, compiled and annotated largely in connection with
coursesoflectures in systematic bacteriology given to graduate students
dents in bacteriology at the Iowa State College during the past fif-
teen years. It is an attempt to bring together material which may
prove of value to those who are desirous of knowing the probable
nomenclatural status of the various names which have been used in
bacterial terminolog3^

If science is to be defined as a system of classified knowledge, the
subject of bacteriology is laboring under a serious handicap in lack-
ing, probably more than any other branch of science, the advantages
conferred by a satisfactory system of terminology or of nomenclature.
It would seem that systematic bacteriology is deserving of even more
recognition at the hands of teachers and investigators than has been
accorded to it in the past.

Systematic bacteriology has two principal aims or functions which
are of importance to the teacher and to the investigator. The first
of these aims has to do with the presentation in graphic form of our
present conception of the phylogeny and of the relationships of various
groups of bacteria. The second is to give a greater degree of stability
to the names used for particular groups of organisms and to prevent
unnecessary nomenclatural confusion in hterature. These aims are
thoroughly scientific, their accompHshment wiU prove useful, we must
therefore accord them careful consideration if our nomenclature is to
be stabiHzed.

It is somewhat difficult to tabulate satisfactorily all of the factors
instrumental in bringing about the present state of confusion and un-
certainty in bacterial terminolog>". That there is such confusion is,
of course, a self-evident fact. It has been rare in texts or articles
(until comparatively recently) to find a consistent use made of generic
names, and systems of classification taught in elementary courses in
bacteriology have rarely been made use of later. In some quarters
there are at the present time certain ill-advised attempts being made

9

10 PREFACE

to standardize nomenclature. Certain American publishers for ex-
ample have sought to fix upon the correct generic names for the desig-
nation of certain micro5rganisms, but apparently with no clear con-
ception of the rules which should govern such standardization.

A study of the catalogs of various colleges and universities in the
United States in which bacteriology is being taught at the present
time reveals the fact that in very few cases are courses offered in which
there is any emphasis placed upon systematic bacteriology and phy-
logeny. An examination of the courses offered in other biological
sciences would show very different conditions. Another factor which
has undoubtedly tended to confuse nomenclature in this science is
the fact that until recent years most bacteriologists received their
training in medical schools. During their medical course they were
familiarized with several systems of nomenclature used in other sciences.
In anatomy, for example, agreement is rapidly being reached that for
each organ and anatomical unit a single international Latin name shall
be adopted, and the student becomes familiar with the general rules
for the formation of such names. In pathology and medicine diseases
are designated in much the same fashion, a descriptive Latin phrase,
frequently consisting of several words, is used. It is exceptional for
the teacher in bacteriology to emphasize the fact that systems of names
used in anatomy and pathologj^ are utterly different and based upon
other rules than those used in naming living plants and animals. Many
of the polynomials which cumber our bacteriological literature have
been applied by workers who do not have such distinctions in mind.
By far the most important factor which has determined the attitude
of teachers and investigators toward this problem has been the lack
of a really adequate system of group differentiation, of classification.
It has taken bacteriological systematists a long time to realize that
such group differentiation (the separation of species and genera),
upon other than morphological differences, may be wholly valid. The
botanical bacteriologist has ignored physiology which is so important.
The physiological bacteriologist has, in many cases, not possessed the
background of the systematist. The latter worker may point out the
characters which should be used, but finds difficulty in their practical
application to the specific problems of taxonomy.

The most hopeful sign of importance in this respect probably, has
been the work of the committee on taxonomy of bacteria of the Society
of American Bacteriologists under the chairmanship of Dr. Winslow,

PREFACE 11

and of the more recent work of a committee on classification of bac-
teria under the chairmanship of Dr. Bergey. The work of Mrs. Enlows
in the names of bacterial genera is also to be commended. It is to be
expected that, as a result of their work, eventually a practical sys-
tem of nomenclature which will be satisfactory and applicable to all
fields of bacteriology will be evolved.

But, it may be asked, is a scientific classification of bacteria really
important and desirable? Are we not making progress in our science
quite as rapidly as we would without the increased emphasis upon
taxonomy? The following statement by H. Marshall Ward, pub-
lished two decades ago is apropos:

"The only really valid objection to a purely scientific classification
is the old objection of the purely utilitarian practical man; and even
there the objection is relative. This leads me to bring out the point
that the bacteriologists in the widest sense of the word are really
looking at the question of classification from at least two very dif-
ferent points of view: On the one hand, we have the botanists, who
direct their attention to the organism, the Schizomycete itself, as a
biological phenomenon to be examined and reported upon as thor-
oughly as possible, for them no classification is complete which does
not record, or (which amounts to the same thing) imply in its records,
all of the life phenomena of the organism, including its pedigree.

"On the other hand, we have the pathologists, hygienists, brewers,
chemists, etc., who regard the organism simply as an object to be named
for convenience in reference, because it brings about certain changes
in tissues, waters, and other media which they are more especially
concerned with. They do not care, and naturally so, what vagaries
the organism exhibits, so long as they can recognize it when they
meet with it. As a matter of experience, however, it is just these
vagaries that bring about the sources of error which beset them on
all hands, and hence they are equally interested with the botanist
in having them cleared up and explained. When we come to the
conclusion that, whatever may be believed to the contrary, the real
interests of bacteriologists of all kinds are identical."

The first chapter of the present volume is devoted to a brief history
of the various classifications of bacteria that have been proposed up
to the present time. An effort has also been made to give dichotomous
keys to the genera and higher groups recognized by the various writers
whenever there seemed to be sufficient data for their formulation.
Contrary to commonly accepted opinion, it will be found that a large

12 PREFACE

number of observers have made contributions in this field, but the
writings are so widely scattered and, in many cases, the journals and
other publications so difficult of access that for the most part they are
quite unknown to our modern writers or, at least, unheeded by them.
It is believed that a synopsis of these various schemes of classification
that have been proposed and a comparison of the various bases upon
which these rest must surely be of service in developing a stable bac-
teriological nomenclature.

The second chapter has to do with codes of nomenclature and their
relationships to the problems of bacterial terminology. The subject
of nomenclature is, in part, distinct from that of classification. The
latter deals with methods and criteria of use in the differentiation of
groups from each other. The former has for its function the deter-
mination of the kind of a name that shall be applied to a group and the
validity and suitability of names which have already been applied.
This frequent confusion of nomenclature in classification has made
us hesitate to give a name to that which we cannot accurately define.
It is true, however, that species have not been accurately delim-
inated in the older biological sciences, but this fact has not interfered
with at least tentative arrangements of the genera and higher groups
nor of application of correct names. It seems to be self-evident that
until the bacteriologists can agree upon a code and follow it consist-
ently, there is little hope or remedy for our present chaos. It is
believed that the discussion of the International Botanical Code given
in this second section will show that it may constitute an adequate
basis, which, with some modification, may prove satisfactory as a
guide.

The third chapter is an alphabetical list of all of the names which
have been used by various authors to designate bacterial subgenera,
genera or higher groups so far as a rather comprehensive study of the
literature has revealed them. Wherever practicable the original de-
scription has been quoted, the descriptions used by various subsequent
writers discussed, and sufficient data included to make possible in
most cases, at least, the formation of an opinion as to the probable
nomenclatural status of each name. It is believed that this list will
prove helpful in the determination of the exact meaning of the various
names, in the formulation of adequate diagnoses for the determination
of synonymy, and in preventing the introduction of new names where
there are valid older names.

PKEFACE 13

The section on bibliography has been compiled with particular care,
as have also the various indices,

I wish gratefully to acknowledge the assistance of many members
of the staff in bacteriology at the Iowa State College, especially Miss
Clarissa Clark, Mrs. C. H. Werkman, Miss Ruth Confare, Mr. J. C.
Weldin and Dr. Max Levine. For interest and assistance in biblio-
graphic details acknowledgment is due Miss Margaret Brown and Prof.
C. H. Brown of the library of Iowa State College.

CHAPTER I

Classification of the Genera and Higher Groups
OF Bacteria

Apparently the first definite named description of any organism in-
cluded now among the bacteria is probably that of Mueller in his
Vermium terrestrium etfluviatilum (1773). The following key, abridged
from his introduction, gives the main groupings and the genera of the
group in which the bacteria fall.

Mueller's Classification of Vermes (1773)

a. Tentaculi destituti.

b. Vagantes Infusoria

c. Organis externis nuUis
d. Teretes.

1. Corpus punctiforme Monas

2. Corpus sphaericina Volvox

3. Corpus cylindraceum .... Enchelis

4. Corpus elongatum Vibrio

5. Corpus cavum Bursaria

dd. Complanati. (With four genera.)

cc. Organis externis. (With four genera.)

bb. Serpentes Helminthica

(With eight genera.)

aa. Tentaculis instruct! Teslacea

(With twelve genera.)

Later in the introduction to the above volume the two genera Monas
and Vibrio (which contain his bacterial species) are noted as found
among the Aquatici, also among the Hyalini, also under Tentaculis
nullis, inconspicui, teretes, and still later under Vacillantes, pellucidi.
Finally he places these genera with Volvox and Enchelis in a classi-
fication imder the headings Organis externis nullis, crassiuscula.

Three species of Monas are described. The generic description is
" Vermis inconspicuus, simplicissimus pellucidus, punctiformus. " The
genus Vibrio is described as " Vermis inconspicuus, simplicissimus,
teres, elongatus." Fifteen species are described. Several of them were
doubtless bacterial forms.

In the year 1786 there appeared a posthumous volume by Mueller,
entitled "Animalcula Infusoria fluviatilia et marina." The infusoria

15

16 GENERAL SYSTEMATIC BACTERIOLOGY

were divided into two groups "Organis externis nullis" and "Organis
externis.'" The forms now included among the bacteria were all to
be found in the ten genera of the first group. These were separated
as follows (p. XXVI) :

Mueller's Classification of Protozoa, etc. (1786)

Crassiuscula

1. Monas: Punctiforme

2. Proteus: Mutabile

3. Volvox: Sphaericum

4. Enchelis: Cylindraceum

5. Vibrio: Elongatum
Membranacea

6. Cyclidium: Ovale

7. Paramoecium: Oblongum

8. Kolpoda: Simatum

9. Gonium: Angulatum
10. Bursaria: Cavum

Two of these genera contained organisms now included among the
bacteria. In the genus Monas were ten species and in Vibrio thirty-
one species. Of these very probably Monas termo, M. punctum and
M. lens, Vibrio lineola, V. rugula, V. bacillus, V. undula, V. serpens
and V. spirillum were bacteria. The monads were spherical or ovoid
in shape, the vibriones longer, and in most species spiral.

Within the next two decades, no advance was made in the classi-
fication of the forms now known as bacteria. However, three generic
names were created by as many writers for organisms supposed to be
fungi, but which many decades later were shown to be bacteria.
The first of these was named by Link (1795), who described Polyan-
gium vitellinum, an organism in its fruiting stages bearing a close resem-
blance to a mold, but which was later shown by Thaxter (1892) to
belong to the Myxobacteriaceae. The second name was applied to the
species Sefmtia marcescens by Bizio (1823) . This investigator had under-
taken to study the cause of an outbreak of "bloody " polenta which was
causing much superstitious fear among the peoples of northern Italy.
He attributed the difficulty to a fungus which developed a red pigment
on farinaceous foods. This was probably the organism now more com-
monly termed Bacillus prodigiosus. Somewhat later Sette (1824,
p. 51) named what is apparently the same organism Zaogalactina ime-
tropha, also regarding it as one of the fungi.

GENERAL SYSTEMATIC BACTERIOLOGY 17

Persoon (1822, p. 96) used the designation Mycoderma mesentericum
for the membrane which appears upon the surface of fermenting alco-
holic solutions, consisting largely of acetic acid bacteria and yeasts.
The organism was classed with the fungi; its relationship to the In-
fusoria of Mueller was not at the time apprehended.

Bory de St. Vincent (1824) created the genus Melanella to include
all non-flexible organisms of the group of Vibrionides whether straight
or spiral. To this genus he transferred four of Mueller's species of
Vibrio. {V. lineola, V. rugula, V. bacillus and V. spirillum).

Bory de St. Vincent (1826) prepared a "Tableau des Ordes, des
Families et des Genres de Microscopiques. " This was a dichotomous
key to genera. A translation of the key carried out to include only the
forms now listed with the bacteria is as follows :

Bory de St. Vincent's Classification (1826)

a. Without Testa.

b. Perfectly smooth, without cilia or other vibratile organs
Order Gymnode
c. Without appendages.

d. Never linear or wormlike. (5 families.)
dd. Linear or wormlike

Family Vibrionides
e. Body opaque.

f. Coiled in a discoid spiral.

STpirilina
ff. Not coiled in a discoid spiral.
Melanella
ee. Body transparent (diaphanous),
f. Attenuate at both tips.

Vibrio
ff. Obtuse.

g. With one end enlarged.

Lacrimatoria
gg. Not enlarged at one end.
Pwpella

Von Baer (1827, p. 748) proposed to establish a genus Lineola to
include all of the extremely minute Infusoria.

The first considerable contributions to our knowledge of bacteria
and their classifications, following Mueller, were those of Ehrenberg
(from 1828-1838) . Certain of his genera of the Infusoria were made up
almost entirely of organisms now included with bacteria. The follow-
ing key will indicate the principal groups of the Infusoria and the posi-
tion of the " bacterial " genera in the system.

18 GENERAL SYSTEMATIC BACTERIOLOGY

Ehrenberg's Classification of the Infusoria (1838)

a. Forms which ingest solid particles, as carmine

Polygastrica
aa. Forms which never ingest particles.

b. Family Monadina. Genus Monas, of which Monas crepusculutn was
probably a bacterium.
bb. Family Vibrionia. Forms which tend to form filaments as a result of
incomplete fission.
c. Cells not flattened.

d. Cells not flexuous.

e. Forming straight rods . . .Bacterium

ee. Forming spiral rods Spirillum

dd. Cells Hfcxuous.

e. Straight rods Vibrio

ee. Spiral rods Spirochaeta

cc. Cells in form of a flattened spiral . . . Spirodiscus

He also described as a member of the diatom genus Gaillonella, a
G. ferruginea now generally included among the bacteria. Later he
changed the spelling to Gallionella. In spite of the fact that it is that
of a recognized diatom genus, this name is still frequently incorrectly
used as a bacterial generic name in the designation of this iron organism.
In the form finally assumed by the Ehrenberg classification (1838) the
bacterial species recognized were as follows: Bacterium triloculare,
Vibrio lineola, V. tremulans, V. subtilis, V. rugula, V. pro-
lifer and V. bacillus, Spirillum undula, S. tenue, Spirochaeta plicatilis
and Spirodiscus fulvus. Later (1840, p. 202) he described Vibrio syn-
cyaneus and V. synianthns.

Kiitzing (1833, p. 385) described as a fresh water alga a form which
he termed Sphaerotilus natans. This is now generally included among
the filamentous water or iron bacteria.

Dujardin (1841, p. 209) used the family designation Vibrionia to
include "Animaux sans organes locomoteurs visibles, se mouvent par
I'effect de leur contractibilite generale." The genera recognized may
be differentiated as follows:

Dujardin's Classification of Vibrionia (1841)

A. Cells straight, non-flexuous, more or less definitely jointed, with slow

wave-like motility Bacterium

B. Cells straight or bent, more or less definitely jointed, flexuous

Vibrio

C. Filamentous forms spiral or screw shaped, never straight, and revolving

rapidly on the axis Spirillum

GENERAL SYSTEMATIC BACTERIOLOGY 19

Trevisan (1842, p. 56) described an organism which he placed among
the algae as closelj'^ related to Oscillatoria. To it he gave the name
Beggiatoa punctata. This genus is now generally recognized as belong-
ing among the sulphur bacteria. In the same year Goodsir (1842,
p. 432) described an organism which he named Sarcina ventriculi. It
occurred as masses of spherical cells forming regular packets in the
vomit of a patient. The relationship of this organism to the types in-
cluded by previous writers among the Infusoria was not recognized.

Kuetzing (1843, p. 198) described one of the iron bacteria, Lepto-
thrix ochracea, which may be regarded as the type species of this genus.
Later Robin (1853, p. 345) named one of the mouth bacteria Lepto-
thrix huccalis. We know now that the two species named are not at all
closely related, but the double use of this designation has led to much
confusion in literature in recent years. Sanitary bacteriologists in
general use the genus Leptothrix for iron bacteria, while many medical
bacteriologists use the name for certain parasitic mouth forms.

Leidy (1849-1852) described several genera of " Entophyta" from
the intestines of arthropods. Several of these, probably Arthromitus,
Cladophytum, Corynocladus^ Cryptodesma, Eccrina, and Enteropryus,
may tentatively be included with the bacteria. It is noteworthy that
in 1849 this author called attention to the probable relationships of the
Vibrio and Bacterium to plants, that is to the Entophyta.

Perty (1852) in his "Zur Kenntniss kleinster Lebensf ormen " di-
vided the Infusoria into Ciliata and Phytozoidia, the latter in turn he
divided into three sections, the third of which he termed Lampozoidea.
The family Vihrionida is included under this. The subfamilies and
genera of the Vihrionida may be differentiated as follows :

Perty's Classification of the Vibrionida (1852)

a. Chains or filaments spirally wound.

Subfamily 1. Spirillina

1. Cells not flexuous Spirillum

2. Cells flexuous Spirochaeta

aa. Filaments flexuous or straight. Subfamily 2. Bacterina

1. Cells flexuous Vibrio

2. Cells not flexuous, cells isolated Bacterium

3. Cells not flexuous, in filaments Metallacter

4. Cells not flexuous, filaments Sporonema

Three species of Spirillum, one of Spirochaeta, three of Vibrio, one
of Bacterium, one of Metallacter and one of Sporonema were described.

20 GENERAL SYSTEMATIC BACTERIOLOGY

Griffith (1853, p. 438) recognized the fact that the Gallionella
ferruginea of Ehrenberg was not a diatom, and created for it a new genus
Didymohelix.

Ferdinand Cohn (1854, p. 123) described as a genus the sUmy bacte-
rial growth which develops in certain solutions, giving it the name
Zoogloea. Later (1872) he abandoned this term recognizing this to be
simply a growth stage in the developmental cycle. Cohn's most im-
portant conclusion at this time was to the effect that the bacteria
(Vibrionien) belong in the plant kingdom rather than with the true
Infusoria.

Henfrej'' (1856, p. 53) described as an alga a form which he termed
Clathrocystis roseo-persinica. This was later placed among the sulphur
bacteria by Winogradsky (1888).

Naegeli (1857, p. 760) first created a definite group in the plant
kingdom for the bacteria. He united the genera Bacterium, Vibrio,
Spirillum, Sarcina, Umbina and Nosema under the group Schizomycetes,
the name by which the bacteria have in general since been known.

Berkeley (1857, p. 313) in his Introduction to Cryptogamic Botany
included two new genera among the molds, Chondromyces and Stigma-
tella. The work of Thaxter has shown these forms to be the fruiting
bodies of myxobacteria.

In 1865 (p. 156) Trecul studied carefully certain vegetable cells which
found developing in putrefying plant tissues. To the various shapes
he gave the names Urocephalum, Amylobacter and Clostridium. These
terms have been sometimes used by subsequent writers as generic names
and ascribed to Trecul, but this ascription is not, strictly speaking,
correct, for this author named no species, his names can be regarded only
as pseudogeneric.

Rabenhorst (1865) in Sectio II, Algas Phycochromaceas Complectens
of his Flora Europaea Algarum included a number of bacterial genera
with the blue green algae. All are included in his order Nematogenae
Family Oscillariaceae. The following key to the three subfamilies and
to the genera of the subfamily Spirillineae will serve to show this author's
conception of relationships.

Rabenhorst's Classification of Bacteria (1865)

A. Filaments more or less destitute of color, flexuous or spirally bent, not
sheathed, often embedded in mucus.

Subfamily 1. Spirillineae

GENERAL SYSTEMATIC BACTERIOLOGY 21

I. Filaments short, cylindric or filiform..!. Vibrio
II. Filaments filiform, articulated, spirally twisted.

2. Spirillum
III. Filament spiral, much elongated 3. Spirochaeta

B. Filaments colored (often only pale blue) sheathed, usually not moving, rarely

slowly oscillating Subfamily II. Leptothricheae.

One genus of the two included, Leptothrix, is often classed with the bacteria.

C. Filaments more or less colored, sheathed, often showing active oscillation.

Subfamily III. Oscillarieae
One genus, Beggiatoa is now generally classed with the bacteria.

As a footnote under the heading '' Fungorum genera Leptothricheis
et O'scillarns quasi affinia:" the following genera are included: Cryp-
tococcus, Ulvina, Sphaerotilus and Hygrocrocis.

In the genus Vibrio the following species are listed, V. lineola,V.
tremulans, V. subtilis, V. rugula, V. purolifer, V. serpens, and V. bacil-
lus. In the genus Spirillum are included Sp. undula, Sp. tenue, Sp.
volutans and Sp. rufum. The single species of Spirochaeta is Sp.
plicatilis.

Hallier (1866) introduced the theory of pleomorphism as applied to
microorganisms. As a result of his work no additional knowledge of
bacterial classification was developed, indeed it was probably somewhat
instrumental in retarding advance. No generic names are to be ascribed
to him, although he introduced certain names to designate what he
believed to be growth forms, and which were later used by various au-
thors as genera.

Davaine (1868) concluded as a result of his study of the anthrax or-
ganism that this microbe was closely related to the other bacteria, but
unlike those previously described, non-motile. To this type he gave the
generic name Bacteridium. A key to the genera of bacteria which he
recognized is as follows:

Davaine's Classification of Bacteria (1868)

a. Filaments straight or bent, never spiral,
b. Motile.

c. Cells rigid Bacterium

CO. Cells flexuous, sinuous Vibrio

bb. Non-motile Bacteridium

aa. Filaments spiral Spirillum

Cohn (1870, p. 108) described one of the filamentous iron bacteria
as Crenothrix poly-spora. Klebs (1871) in conformity with his ideas on
bacterial pleomorphism gave the name Microsporon septicum to the
pleomorphic organism which he associated with pus infections.

22 GENERAL SYSTEMATIC BACTERIOLOGY

Cohn (1872, p. 229) named a spherical organism which he found in
smallpox lymph the Microsphaera vacciniae. Later the fact that this
generic name had been previously used for a genus of Ascomycetes
led him to change to the generic name Micrococcus.

The first measurably adequate classification of bacteria following
the recognition of the fact that they were plants, not animals, was that
of Cohn (1872, p. 127). He defined the bacteria as having cells free
from chlorophyll, spherical, oblong or cylindric, straight or bent^
multiplying exclusively by fission and either isolated or vegetating in
cell families. Four tribes with a total of six genera were recognized.
They may be differentiated by reference to the following key :

Cohn's Classification of Bacteria (1782)

A. Cells spherical Tribe I. Sphaerobacteria

One genus only 1. Micrococcus

B. Cells isolated short rods .Tribe II. Microbacteria

One genus only 2. Bacterium

C. Cells elongate or in filaments Tribe III. Desmobacteria

1. Cells not flexuous 3. Bacillus

2. Cells flexuous 4. Vibrio

D. Cells spiral Tribe IV. Spirobacteria

1. Cells not flexuous 5. Spirillum

2. Cells flexuous 6. Spirochaete

It will be noted that one new genus, Bacillus, was created with B,
sublilis as the type. Two other species, Bacillus ulna and B. anthracis
were included.

Billroth (1874) in a volume entitled "Untersuchungen iiber die Veg-
etationsformen von Coccobacteria septica," revived in a modified form
the Hallier theory of pleomorphism. As the result of extended studies
he came to the conclusion that various bacteria which he observed were
different growth forms of the organism which he termed Coccobacteria
septica. To the various growth forms he gave names, such as Micro-
coccos, Mesococcos, Megacoccos, Microbacteria, Mesobacteria, Mega-
bacteria, Monococcos, Monobacteria, Petalococcos, etc. With a modified
spelling some of these names have been used by subsequent writers
as generic names for bacteria, and by some have been credited to Bill-
roth. This is incorrect as the names were not used by this author in
a generic sense, and had no species named.

Cohn (1875, p. 141) later greatly extended and improved his classi-
fication of bacteria. He concluded that they belonged with the blue
green algae, differing principally in the absence of chlorophyll. His.
complete classification is as follows.

GENERAL SYSTEMATIC BACTERIOLOGY 23

Cohn's Classification of the Schizophyta (1875)

a. Cells free or united into slimy families by an intercellular substance.

Tribe I. Gloeogenae
b. Cells free or in twos or fours.

c. Cells spherical Chroococcus Naeg.

cc. Cells cylindrical Synechococcus Naeg.

bb. Cells in resting stage united into amorphous slimy families.
0. Cell membranes continuous with intercellular substance,
d. Cells without phycochrome, very small.

e. Cells spherical Micrococcus Hall, emended

ee. Cells cylindrical Bacterium Duj.

dd. Cells with phycochrome, larger.

e. Cells spherical Aphanocapsa Naeg.

ee. Cells cylindrical Aphanothece Naeg.

cc. Intercellular substance formed of layers of cell membranes.

d. Cells spherical Gloeocapsa Kg. Naeg.

dd. Cells cylindrical Gloeothece Naeg.

bbb. Cells united into definite slimy families.

c. Cell families of a flat single layer of cells.

d. Cells in fours in one plane. . . .Merismopedia Meyen.
dd. Cells irregularly grouped on surface of sphere,
e. Cells spherical, families broken into nets.

Clathrocystis Henfr.

ee. Cells cylindric Coelosphaerium Naeg.

cc. Cell families, many layered, united into spherical cell bodies,
d. Number of cells definite.

e. Cells spherical, in tetrads, colorless.

Sarcina Goods
ee. Cells cylindric, not regularly arranged, with phyco-
chrome Gomphosphaeria Kg.

dd. Number of cells indefinite, very large.
e. Cells colorless, very small.

Ascococcus Billr. emended
ee. Cells with phycochrome, larger.

Polycystis Kg.
Coccochloris Spr.
Polycoccus Kg.

aa. Cells united into filaments Tribe II. Nematogenae Rab.

b. Cell filaments always unbranched.

c. Filaments free or felted together.

d. Filaments cylindric, colorless, indefinitely jointed,
e. Filaments very slender, short.

Bacillus Cohn
ee. Filaments very slender, long.

Leptothrix Kg. em. /*f\VvVC>^/
eee. Filaments thicker, long . .i?eogia<oo Trev. /v/^-^rkiT .■'^v

24 GENERAL SYSTEMATIC BACTERIOLOGY

dd. Filaments cylindric, with phycochrome, definitely jointed.
Reproductive cells unknown.

Hypheothrix Kg.
Oscillaria Bosc. u. a.
3d. Filaments cylindric, jointed, forming gonidia.

e. Colorless Crenothrix Cohn

ee. With phycochrome Chamaesiphon u. a.

4d. Filaments spiral.

e. Without phycochrome.

f. Filaments short, slightly wavy.

VibiHo Ehr. em.
ff. Filaments short, spiral, stiff.

Spirillum Ehr.
fff. Filaments long, spiral, flexuous.

Spirochaete Ehr.

ee. With phycochrome Spirulina Link

5d. Filaments rosary like.

e. Colorless Streptococcus Billr.

ee. With phycochrome Anabaena Bory.

6d. Filaments tapered to tip Spermosira Kg. u. a.

cc. Filaments united together into slimy families.

d. Filaments cylindric, colorless. Myconos<oc Cohn
dd. Filaments cylindric, with phycochrome.

Chthonoblastus-Limnochlide

3d. Filaments rosary like Nostoc, Hormosiphon u. a.

4d. Filaments tapering to tip Rivularia Roth

bb. All filaments with false branches.

c. Filaments cylindric, colorless Cladolhrix Cohn

Streptothrix Cohn
cc. Filaments cylindric, with phycochrome.

Calothrix Ag.

3c. Filaments rosary like Merizomyria Kg.

4c. Filaments tapering Schizosiphon Kg.

It will be noted that the following bacterial genera were new,
Ascococcus (species A. Billr othii), Streptococcus (erroneously ascribed to-
Billroth, even here without a species designation and probably therefore
invalid) Myconostoc {M. gregarium), Cladothrix (sp. C. dichotoma, name
invalid because earlier used for another genus of plants), Streptothrix
{Str. Foersteri, generic name invalid because of previous use of this
generic name for a genus of fungi) .

It has been suggested that if a date for a point of departure for the
classification of bacteria is to be fixed it might well date from this
1875 classification of Cohn.

In 1877 the veterinarian Bollinger sent to the botanist Harz purulent
material from a case of "lumpy jaw" in a cow. Harz found present

GENERAL SYSTEMATIC BACTERIOLOGY 25

an organism which he named Actinomyces bovis, the type of a group of
organisms now recognized as showing many intermediate characters
between the true bacteria and the fungi. Rivolta (1878, p. 169) ob-
jected to this name, and proposed in its place Discomyces bovis.

McNab (1877, p. 340) outhned a classification of the ''Vegetable
Kingdom." His lowest group was the Subkingdom Thallophyta,
with several classes. The first of these he termed Schizophyta or
Protophyta. The orders and families were as follows:

McNab's Orders of the Schizophyta (1877)

Order I. Cyanophyceae or Phycochromaceae

Families. Chroococcaceae, Nostocaceae, Oscillatoriaceae, Rivulari-
aceae, Scytonemaceae
Order II. Chlorophyllophyceae

Families. Palmellaceae, Euglenaceae
Order III. Schizomycetes

Family. Bacteriaceae
Order IV. Saccharomycetes

Family. Saccharomyceae

Van Tieghem (1878, p. 198) introduced the generic name Leuconostoc
to designate a streptococcus-like form occurring in large gelatinous
masses in syrup, an organism previously described by Cienkowski
(1878, p. 12) as Ascococcus mesenter aides.

Magnin (1878) in his text "Les Bacteries" reviewed at length the
classification of bacteria, and adopted the scheme of Cohn.

Miquel (1879-1881) published a series of articles on the organisms
which produce ammoniacal fermentation in urine. He introduced the
generic names Urobacillus, Urococcus and Urosarcina for bacilli, cocci
and sarcinae which could bring about this change.

Trevisan (1879, p. 13) created several new genera of bacteria, and
evolved the following classification.

Trevisan's Classification of Bacterial Genera (1879)

a. Unicellular bacteria, globose or cylindric. Spores solitary within the cells.
Multiplication by division of the cells in one, two, or all directions.

Tribe I. Bacterieae
b. Cells free or when quiescent associated in indeterminate mucous

colonies Subtribe I. Eubacterieae

c. Cells globose or globose ovoid. Multiplication by vegetative
division of the cells in all directions

Genus 1. Micrococcus

26 GENERAL SYSTEMATIC BACTERIOLOGY

cc. Cells short cylindric, ellipsoid or fusiform. Multiplication by
division of the cells always in the same direction.
Genus 2. Bacterium
bb. Cells associated by an intercellular substance into regular mucous

colonies Subtribe II. Sarcineae

c. Cells globose, or when dividing ovoid, associated in tetrads in
tabular colonies, surrounded by a thick gelatinous tegument.
No common capsule about entire colony.
Genus 3. Sarcina
cc. Cells globose, or ovoid when dividing, associated in many layers
in dense colonies, surrounded by 1 to 4 gelatinous teguments.
No common tegument about entire colony.

Genus 4. Chlamydatomus
ccc. Cells globose, associated in large numbers in globular colonies
without separate capsules. Colonies surrounded by a common
gelatino-cartilaginous tegument.

Genus 5. Ascococcus

aa. Pluricellular bacteria. Individuals composed of numerous cells frequently
in a filiform body. Spores in series within the cells. Cell division always
transverse.

Tribe II. Vibrionieae

h. Free, without branching. . . Subtribe I. Euvihrionieae

c. Somatia fusiform or cylindric distinctly articulate, short,

straight, isolated Genus 6. Maniegazzaea

2c. Somatia cylindric, more or less distinctly articulate, slender,
short, straight, isolated.

Genus 7. Metallacter
3c. Somatia cylindric, more or less distinctly articulate, slender,
elongate, filiform, straight, loosely fasciculate.
Genus 8. Leptotrichia
4c. Somatia cylindric, more or less distinctly articulate, elongate,
filiform, straight, loosely aggregated.

Genus 9. Beggiatoa
'5c. Somatia cylindric, distinctly articulate, elongate, arcuate or
twisted, in masses, microgonidia formed from cells by repeated
transverse and longitudinal divisions, globulose, in dense masses
in a terminal pseudo-sporangium, escaping from the tip.
Genus 10. Crenothrix
6c. Somatia cylindric, articulate, short, undulate flexuose.

Genus 11. Vibrio
7c. Somatia cylindric, articulate, short, rigid, spirally twisted.

Genus 12. Spirillum
8c. Somatia cylindric, distinctly articulate, elongate, flexile, spiral.

Genus 13. Spirochaete
9c. Somatia compressed like a blade, short, spirally twisted.

Genus 14. Spiromonas

GENERAL SYSTEMATIC BACTERIOLOGY 27

bb. Somalia associated into colonies through intercellular mucxxs.

Unbranched Subtribe II. Myconostoceae

c. Somalia cylindric, slender, implicate, twisted, invested in mucus,
in globular colony . . . .Genus 15. Myconostoc
bbb. Somalia free, pseudoramose.

Subtribe III. Cladothriceae
c. Somalia cylindric, leptothrichoid, lower portion scarcely articu-
late, slender, straight or slightly bent, pseudo-dicholomous.
Microgonidia formed by a series of successive longitudinal and
transverse divisions, globose, in a pseudo-sporangium, escaping
laterally and developing new Somalia.

Genus 16. Cladothrix
cc. Somalia cylindric, leptothrichoid, indistinctly articulate, slender,
straight or slender spirals, sparsely branched.
Genus 17. Streptothrix

Luerssen (1879) in the first volume of his Botanik discusses the genera
of bacteria. Those recognized by him may be differentiated as follows :

Luerssen's Classification of Bacteria (1879)

a. Cells not united in filaments, after division quickly falling apart or remain-
ing in pairs, free or united into colonies by mucus,
b. Cells divide in one plane.

c. Cells spherical 1. Micrococcus

cc. Cells ellipsoidal or short ellipsoidal

2. Bacterium
bb. Cells dividing regularly in three directions of space forming cubical

packets 3. Sarcina

aa. Cells in cylindrical threads.

b. Filaments straight, indefinitely jointed.

c. Filaments very slender and short, rod shaped.

4. Bacillus
cc. Filaments very slender and long. . . .5. Leptothrix

ccc. Filaments thick and long 6. Beggiatoa

bb. Filaments wavy or spiral.
c. Short and stiff.

1. Filaments slightly curved 7. Vibrio

2. Filaments spiral 8. Spirillum

cc. Long, flexuous 9. Spirochaete

Duclaux (1879-80) in his extensive "Memoire sur lelait" described
with the generic name Tyrothriz a considerable number of organisms
isolated from milk and cheese. The species are not closely related,
and the group decidedly heterogeneous, the name in consequence has
been but little used. The same may be said of the generic name
AcHnohacter (species A. polymorphum which he isolated from milk).

Winter (1880) published in the volume "Die Pilze" of Rabenhorst's
Kryptogamen-flora one of the most extensive classifications made up to
this time. The key to the genera follows :

28 GENERAL SYSTEMATIC BACTERIOLOGY

Winter's Classification of Bacteria (1880)

a. Cells spherical or oval.

b. Cells isolated, in chains or embedded irregularly in mucus.

1. Micrococcus Cohn
bb. Cells united into definite colonies.

c. Colony hollow, with peripheral layer of cells.

2. Cohnia Winter
cc. Colony solid, filled with cells.

d. Cells united in small but definite numbers into regular

families 3. Sarcina Goodsir

dd. Cells in large and indefinite numbers united into irregular

colonies 4. Ascococcus Cohn

aa. Cells cylindric, short or long.

b. Cells short, cylindric, single or bound loosely together in pairs

5. Bacterium
bb. Cells longer, cylindric, united into filaments.

c. Filaments isolated or felted.
d. Unbranched.

e. Cells straight.

f. Short, definitely jointed

6. Bacillus Cohn
ff. Long, indefinitely jointed.

g. Very slender. . .7. Leptothrix Kiitzing

gg. Thicker 8. Beggiatoa Trevisan

ee. Cells spiral or bent.

f. Cells short, with few turns, not flexuous.

9. Spirillum Ehr.

ff. Cells longer, with numerous turns, flexible.

10. Spirochaeta Ehr.
dd. With apparent branches 11. Cladothrix Cohn

cc. Cells embedded in rounded gelatinous masses.

12. Myconostoc Cohn
aaa. Cells lancet-like; flat bands, spirally wound. .13. Spiromonas Perty

In an "Anhang" he includes two other genera, Sphaerotilus Kiit-
zing and Crenothrix Cohn. The name Cohnia used as generic designa-
tion by Winter was preoccupied, and changed later by Schroeter to
Lamprocystis.

Prazmowski (1880) in a study of certain anaerobic bacteria revived
Trecul's casual name Clostridium, and created a genus with this designa-
tion to include those organisms which produce spores in more or less
spindle-shaped cells.

De Lanessan (1880) gave an outline of a classification of the genera of
bacteria as follows:

GENERAL SYSTEMATIC BACTERIOLOGY 29

de Lanessan's (1880) Classification of Bacteria

A. Cells not united in filaments, separating immediately after division, or in

colonies (zoogloea) united by a gelatinous substance.
I. Cells dividing in one direction only.

a. Cells spherical Micrococcus

b. Cells elliptical or short cylindrical.. . .Bacterium

II. Cells dividing regularly in three directions of space, forming cubical
colonies Sarcina

B. Cells cylindrical in filaments.

I. Filaments straight, imperfectly segmented.

a. Filaments very slender and short, small rods.

Bacillus

b. Filaments slender and long Leptothrix

c. Filaments broader and long Beggiatoa

II. Filaments undulant or spiral.

a. Filaments short.

1. Filaments slightly undulant .... Vibrio

2. Filaments spiral, stiff Spirillum

b. Filaments long, flexible, with rapid undulations, spiral throughout

length, slender, actively motile . . .Spirochaeta

Bergonzini (1881) named a violet organism which he studied Cromo-
hacterium violaceum.

Kern (1882, p. 135) studied the organism producing a Caucasian
fermented milk beverage. Because it apparently produced two spores
to a cell he named it Dispora caucasica. Either Kern mistook other
cell inclusions for spores or confused spore-bearing bacteria with the
sour milk form. His organism cannot be satisfactorily identified from
his description, and the genus name has not been used by other writers.

Zopf (1883) in the first edition of his ''Die Spaltpilze" formulated
a somewhat new characterization of bacterial genera. The families
and genera recognized may be separated as follows:

Zopf s Classification of Bacteria (1883)

a. Cells spherical, sometimes in filaments made up of coccal elements. One

genus only Leuconostoc

aa. Organisms showing coccus and rod shapes in growth stages.

b. Spiral forms lacking as a growth stage. Filamentous stage showing
no differentiation of base and tip.

e. Not becoming spindle or club shaped when sporulating.

Bacterium
cc. Rods becoming spindle shaped or ellipsoidal or club shaped
when sporulating Clostridium

30 GENERAL SYSTEMATIC BACTERIOLOGY

bb. Possessing spiral stage in the growth,
c. Not forming false branches.

Leptothrix, Beggiatoa, Crenothrix and Phragmidiothrix
cc. Fonning false branches Cladothrix

Balcke (1884) according to Lindner named an organism from ferment-
ing wort Pediococcus cerevisiae. This generic name has been commonly
used since as a designation for organisms which occur in tetrads but do
not form regular Sarcina packets.

De Bary (1884) introduced a new principle into the classification
of bacteria by his separation of these organisms into two groups based
upon the presence of endoepores in the one and of arthrospores in the
other. The following key will illustrate this method of differentiation :

De Bary's Classification of Bacteria (1884)

a. Producing endospores.

b. Rods straight or slightly bent (including all non-arthrosporous types
of Clostridium, Bacteridium, Vibrio, etc.)

1. Bacillus

bb. Rods spiral 2. Spirillum

aa. Producing arthrospores.

b. Rosaries of cocci, embedded in firm masses of gelatin.

3. Leuconosto'c

bb. Simple rods 4. Arthrobacterium

bbb. Filamentous forms 5. Crenothrix

6. Beggiatoa

7. Cladothrix

8. Leptothrix

The classification used by Grove (1884) was an exact translation of
that of Winter.

Van Tieghem (1884) agreed with Cohn in including the bacterial
genera among the blue-green algae. The following key, carried to gen-
era only for the bacteria, will illustrate the rather indefinite group-
ing used by this author.

Van Tieghem's Classification of Bacteria (1884)

A.^Family I. Nostocaceae. Producing cysts. With many algal genera and the

bacterial genera Beggiatoa and Leuconostoc.
B. Family II. Bacteriaceae. Producing spores.
I. Cell division in one direction of space.
a. Cells spherical. Micrococcus
(In gelatin, Ascococcus, Naked, Punctula.)

GENERAL SYSTEMATIC BACTERIOLOGY 31

b. Cells elongate.

1. Cells not spiral.

(a) Cells separating when formed.

Bacterium

(b) Cells forming a chain or filament.

Bacillus

(c) Filaments relatively long.

(1) Sheathless Leptothrix

(2) Sheathed Crenothrix

(d) Filaments branched Cladothrix

(e) Enclosed in gelatin Ascobacteria

(f ) Naked cells Polybacteria

2. Cells spiral.

(a) Cells separating quickly.. Fz6no

(b) Spiral, like a spring Spirillum

(c) Cells longer and more slender.

Spirochaete

(d) Cells embedded in gelatin.

Myconostoc
II. Cell division in two directions of space, giving rise to tetrads.

Merista
III. Cell division in three directions of space forming cubical packets.

Sarcina

The genera Streptococcus for the chain cocci and Staphylococcus
for the irregularly grouped cocci from pus were first adequately defined
by Rosenbach (1884). Both of these names had previously been used
by other writers, but Rosenbach was apparently the first to associate
them definitely with species.

Zopf (1884) in the third edition of Die Spaltpilze materially modi-
fied and enlarged the bacterial classification used in the first and second
editions. The four main groups were recognized as before, but the
number of genera increased. Following is the classification used:

Zopf s Classification of Bacteria (1885)

a. Cells producing only a spherical stage.

b. Not embedded in firm masses of gelatin,
c. Cells regularly arranged.

d. Cells in chains Streptococcus

dd. Cells not in chains.

e. Cell division in two planes, forming flat plates of

cells Merismopedia

ee. Cell division in three planes, forming regular cubes and

packets Sarcina

cc. Cells irregularly arranged Micrococcus

32 GENERAL SYSTEMATIC BACTERIOLOGY

bb. Cells embedded in thick gelatinous masses.

Ascococcus
aa. Consisting of cocci, rods and filaments, or the latter two forms only; in
filaments no differentiation of base and tip.
b. Spore formation unknown or not occurring.

c. Cells not spiral Bacterium

cc. Cells spiral Spirillum

bb. Spore formation known.

c. Filaments spiral Vibrio

cc. Filaments not spiral.

d. Forming cocci and rods, spore formation in the former.

Leuconostoc
dd. Forming cocci and rods or latter only. Spores in rods or

cocci Bacillus

ddd. As in dd, but spores in swollen cells.

Clostridium
3a. Consisting of coccus, rod and filament forms, the latter with a differentiation
of base and tip.
b. Filaments containing sulphur, sheathless.

Beggiatoa
bb. Filaments without sulphur.

c. Filaments sheathed Crenothrix

cc. Filaments not sheathed, cell divisions ultimately both longitudi-
nal and transverse Phragmidiothrix

ccc. Filaments with or without sheaths, no longitudinal cell division.

Leptothrix
4a. Consisting of cocci, rods, filaments and spirals. False branching occurs.
Spore formation is unknown Cladothrix

Trevisan (1885) described several new genera of bacteria, including
Kurthia, Zopfiella, Bacteriopsis, Klebsiella and Gaffkya.

In the same year he also created the genus Pacinia to include or-
ganisms of the type of the Asiatic cholera organism.

Hauser (1885) described a new genus Proteus to include certain put-
refactive bacteria which formed characteristic amoeboid colonies on
gelatin and which exhibited a high degree of pleomorphism, varying
from cocci to rods and spirals.

Lutz (1886) proposed the generic name Coccothrix to designate the
acid fast bacteria of the types of the organisms of tuberculosis and of
leprosy. He also made this genus the type of the family Coccothricha-
ceen. In the same year Weichselbaum used the designation Diplo'
coccus pneumoniae for the causal organism of pneumonia.

Fliigge (1886) outlined a classification of bacterial genera which
has been extensively followed by medical bacteriologists. A key to
his genera may be constructed as follows:

GENERAL SYSTEMATIC BACTERIOLOGY 33

Fltigge's Classification of Bacteria (1886)

a. Cells spherical.

b. Cells isolated, or bound in chains united into amorphous slimy families.

1. Micrococcus
bb. Cells united into definite slimy families.
c. Colonies solid (filled with cells).

d. Cells united in large and indefinite numbers into irregular

colonies 2. Ascococcus

dd. Cells in small but definite numbers united into regular fami-
lies 3. Sarcina

cc. Colonies with peripheral layers of cells, no cells in the interior.

4. Clathrocystis
aa. Cells cylindric.

b. Cells short cylindric, single or loosely hanging together, or united into

amorphous slimy masses 5. Bacterium

bb. Cells longer cylindric, bound into filaments.

c. Filaments isolated, in filaments or in bundles,
d. Filaments unbranched.
e. Filaments straight.

f. Filaments short, definitely jointed.

6. Bacillus

ff. Filaments long, indefinitely jointed,
g. Filaments very slender.

7. Lepiothrix
gg. Filaments thicker.

8. Beggiatoa
ee. Filaments undulating or spiral.

f. Short, stiff 9. Spirillum

(Vibrio)

ff . Long, flexible 10. Spirochaeta

dd. Filaments with false branches.

11. Streptothrix

12. Cladothrix
cc. Filaments enclosed in round gelatinous masses.

13. Myconostoc

Genera doubtfully belonging here: Crenothrix, Sphaerotilus, Spir-
omonas, Rhahdomonas, Monas.

Schroeter (1886) outlined the most complete and elaborate class-
ification of bacterial genera and species that had been prepared up to
that time. He introduced a number of new genera. His generic key is
as follows:

Schroeter's Classification of Bacteria (1886)

I. Order: Coccohacteria. Cells in all stages of development, spherical-
elliptical, never motile. Spores, if present, developing through trans-
formation of an entire cell. . .Family Coccaccei Zopf.

34 GENERAL SYSTEMATIC BACTERIOLOGY

A. Cells or colonies free or embedded in slime, without definite gelatinous

membranes.

1. Cells single or arranged irregularly Micrococcus Cohn

2. Cells united in chains Streptococcus Billroth.

3. Cells united in a stratum.

a. In tabular form Lampropedia n. g.

b. In hollow balls Lamprocystis n. g.

B. Single cells or cell colonies with a definite firm gelatinous covering

(cyst).

1. Cells single or irregularly grouped:

a. Each cell or small cell family included in a simple gelatinous

cyst Hyalococcus n. g.

b. Cells or few celled families included in a many layered slime

capsule Leucocystis Schroeter

c. Cell families of many cells enclosed in an almost solid gelat-

inous mass Ascococcus Billroth

2. Cell families regularly formed:

a. Cell families in packet-shaped bundles, each single cell with a

capsule Sarcina Goodsir

b. Cells in chains, each family in a capsule.

Leuconostoc Van Tieghem
II. Order: Eubacteria. Cells rod shaped, shorter or longer.

Family Bacteriacei

A. Cells or cell groups without definite gelatinous capsule.

1. Cells straight or slightly bent, not spiral.

a. Cells very small, elliptical, motile or non-motile, spores

unknown Bacterium Ehr.

b. Cells cylindrical, motile or non-motile :

(1) Cells relatively very broad. Red, with sulfur.

Chromatium Perty

(2) Cells in vegetative condition narrow rods. Endoge-

nous spores.

(a) Spore bearing cells cylindric.

Bacillus Cohn

(b) Spore bearing cells spindle shaped.

Clostridium Praz.

2. Cells and cell chains spiral, usually actively motile.

a. Spirals stiff (not flexuous). Endogenous spores.

Spirillum Ehr.

b. Spirals flexuous:

(1) Cells known only in the form of a long flexuous spiral.

Spores unknown Spirochaete Ehr.

(2) Cells in greater part of life only with short (§) spiral,

later growing to screw form. Spores spherical.
Arthrospores Microspira n. g.

B. Cells enclosed in definite gelatinous masses.

1. Cells wound in small numbers in a transparent capsule.

Myconostoc Cohn

GENERAL SYSTEMATIC BACTERIOLOGY 35

2. Cells rod shaped, in large numbers in a brown thick capsule.

Cystobacter n. g.
III. Order: Desmobacteria. Long filaments, usually surrounded by a definite
sheath :

A. Filaments unbranched Family Leptotrichacei Zopf.

1. Filaments always non-motile.

a. Filaments with very thin sheaths. Multiplication by falling

apart into two segments Leptothrix Ktitzing

b. With thick sheaths. Multiplication by spores and separation

of single joints Crenothrix Cohn

2. Filaments motile Beggiatoa Trevisan

B. Filaments branched:

1. Filaments not club shaped or thickened at end:

a. Filaments free Cladothrix Cohn

b. Filaments bound in bundle by slimy capsule.

Sphaerotilus Kiitzing

2. Filaments club thickened at end.. . .Actinomyces Harz.

The new genera described were Lampropedia, Lamprocystis, Hyalo-
coccus, Leucocystis, Microspira and Cystobacter.

Trevisan (1887) outlined the following classification of bacterial
genera.

Trevisan's Classification of Bacteria (1887)

1. Bacteriaceae trichogenae. Three stages of vegetative development.
1. Filaments (typical). 2. Rods. 3. Cocci.

A. Filaments fixed, with base distinct from tip.

(Lepiotrichieae) .
Genus 1. Cladothrix Cohn
Genus 2. Crenothrix Cohn
Genus 3. Sphaerotilus Kiitzing
Genus 4. Leptotrichia Trevis. (1879)
Genus 5. Beggiatoa Trevis. (1842)
Genus 6. Phragmidiothrix Engler (1881)

B. Filaments free, no distinction between base and tip.

1. Filaments spiral, not embedded in a mucous capsule. (Spirilleae).

Genus 7. Kurthia. Trevis. (1885)
Genus 8. Vibrio Cohn (1872)
Genus 9. Spirillum Ehrenb.
Genus 10. Spirochaete Ehrenb.

2. Filaments spiral, embedded in mucous capsule (Myconostoceae) .

Genus 11. Myconostoc Cohn

3. Filaments straight. (Zopfielleae).

Genus 12. Zopfiella Trevisan (1885)
II. Bacteriaceae baculogenae. Three stages of vegetative development.

1. Rods (tvpical). 2. Filaments (abnormal or transitory stage). 3. Cocci.

36 GENERAL SYSTEMATIC BACTERIOLOGY

A. Notcapsulated. {Bacilleae).. . .Genus 13. Bacillus Cohn

Genus 14. Pacinia Trevis. (1885)

Genus 15. Clostridium Prazmowski

Genus 16. Pasteurella Trevis.

Genus 17. Bacterium Cohn (1872)

Genus 18. Bacteriopsis Trevis. (1885)

B. Normally capsulated. (Klebsielleae) .

Genus 19. Klebsiella Trevis. (1885)
III. Bacteriaceae coccogenae. One stage only of development, coccus.

A. Cocci enclosed in common membranous mucous capsule {Ascococceae).

Genus 20. Leuconostoc Van Tieghem
Genus 21, Ascococcus Cohn
Genus 22. Gaffkya Trevis. (1885)

B. Cocci in packets, chains, or isolated. No capsules.

Genus 23. Sarcina. Goodsir

Genus 24. Staphylococcus Ogston

Genus 25. Streptococcus Zopf.

Genus 26. Micrococcus Cohn (emend)

Maggi (1887) in his "Acque potabili" outlined a bacterial classifica-
tion as follows:

Maggi's Classification of Bacteria (1887)

A. Order I. Spirobacteria Cohn

I. Genus 1. Spirochaeta Ehr.
II. Genus 2. Spirillum Ehr.
III. Genus 3. Vibrio Auct. emend.

B. Order II. Desmobacteria Cohn

I. Genus 1. Cladothrix Cohn
II. Genus 2. Crenothrix Cohn

III. Genus 3. Beggiatoa Trevisan

IV. Genus 4. Leptothrix Kiitzing
V. Genus 5. Bacillus Cohn

C. Order III. Microbacteria Cohn

I. Genus 1. Bacterium Dujardin emend.
II. Genus 2. Zygobacterium Maggi.

D. Order IV. Sphaerobacteria Cohn

I. Genus 1. Micrococcus.

The new genus Zygohaderium with its single species Z. nitrosum
does not seem to be adequately described. The figures show slender
rods lying parallel to each other in pairs.

Metschnikoff (1888) described as Pasteuria ramosa an organism which
he concluded was a bacterium which divided longitudinally rather than
transversely. Although this generic name has been used by subsequent
writers as a bacterial genus, it is probable that it is best regarded as
protozoan.

GENERAL SYSTEAL\TIC BACTERIOLOGY 37

Winogradsky (1888) reported the results of a stud}- od the morphology
and physiologj^ of the sulphur bacteria. A number of new genera were
created, and several old genera brought definitely into this group. To
the present time the account given by this author is the only recorded
observation of certain of these forms. His key for the separation of
these sulphur genera may be translated as follows:

Key to Winogradsky's Genera of Sulphur Bacteria (1888)

A. Colorless sulphur bacteria.

I. Filaments uniform in thickness, always free, motile, forming no

gonidia Beggiatoa

II. Filaments of variable thickness, attached forming motile rod gonidia.

Thiothrix

B. Red sulphur bacteria.

I. Cells united into families.

a. Division of cells in three planes.

1. Families of cells small, solitary or many surrounded by a

gelatinous cyst, swarming. . . . Thiocystis

2. Families of cells spread out on a substrate, spherical cells

embedded in a common gelatin, not swarming.

Thiocapsa

3. Families packet shaped Thiosarcina

h. Division of cells first in three planes, then in two. Families first
solid, then hollow Lamprocystis

c. Division of cells in two directions of space. Families tabular,

tetrads, swarming Thiopedia

d. Division of cells in one plane.

1. Families amoeboid motile. Cells united by plasma threads.

Amoehohacter

2. Families with thick gelatinous cysts. Cells in common

gelatin, very loosely embedded, swarming.

Thiothece

3. Families of rods united into a net.

Thiodictyon

4. Families solid, non-motile, of small cells closely appressed.

Thiopolycoccus
II. Cells free, alwaj-s swarming.

a. Cells cylindric-elliptic Chromatium

b. Cells rod and spindle shaped Rhabdochromatium

c. Cells spiral Thiospirillum

Hansgirg (1888, p. 229) called attention anew to the parallelism ex-
isting in morphology in the bacteria and the algae. He gives as an
illustrative table the following :

38

GENERAL SYSTEMATIC BACTERIOLOGY

Hansgirg's Comparison of Bacteria and Blue-green Algae (1888)

Bacteria Blue Green Algae

Micrococcus-Hyalococcus A phanocapsa-Chrococcus

Bacterium-Streptococcus A phanothece-Synechococcus

Leucocystis-Mycothece Gloeocapsa-Gloeathece

Ascococcus-Leuconosloc Polycoccus-Anacystis (Polycystis)

Lamprocystis {Cohnia)-Sarcina . Clathrocystis-Merismopedium

{Lampropedia) Lyngbya exp. {Leptothrix exp. Hypheo-
Bacillus-Leptothrix exp. thrix)

Beggiatoa-Spirochaete (Spirillum) Oscillaria-Spirulina

Myconostoc Nostoc

Crenothrix Chamaesiphon

Cladothrix (Streptothrix) Plectonema [Glaucothrix)

He also prepared an outline of the groups of bacteria with particular
reference to the forms to be found in damp cellars and other subterranean
habitats. While adequate descriptions are not given by Hansgirg,
the following key is believed to represent the principal distinctions among
the various groups.

Hansgirg's Classification of Bacteria (Schizomycetes) (1888)

A. Filamentous Order I. Desmobacteria

I. With false branching. . . .Family Cladothricaceae

One genus only Genus Cladothrix Cohn

II. No false branching.

a. Gonidia formed Family Crenothricaceae Hansg.

One genus only Genus Crenothrix Cohn

b. No gonidia Family Leptothricaceae

1. Filaments immobile.

Subfamily Leptothriceae
One genus only. . . .Genus Leptothrix Ktz. ex. p.

2. Filaments oscillating.

Subfamily Beggiatoeae Hansg.
One genus only Genus Beggiatoa Trevisan

(a) Filaments not colored.

Sec. 1. Eubeggiatoa Hansg.

(b) Filaments colored purple.

Sec. 2. Chromobeggiatoa Hansg.

B. Cells elongate, but not filamentous.

Order II. Euhacteria

I. Cells not encysted Family Bacteriaceae

a. Cells spirally bent. ..Subfamily Spirobacteria. Cohn

1. Cells flexuous Genus Spirochaete. Ehrb.

2. Cells not flexuous. . .Genus Spirillum Ehrb.

(a) Colorless, without sulphur.

Section 1. Vibrio (Cohn) Hansg.

(b) Rose colored, with sulphur.

GENERAL SYSTEMATIC BACTERIOLOGY 39

Section 2. Ophidomonas (Ehr.) Hansg.
b. Cells not spirally bent.

Subfamily Microbacteria Cohn

1. Cells elongate Genus Bacillus Cohn

(a) Without sulphur inclusions.

Section 1. Eubacillus Hansg.

(b) With sulphur inclusions.

Section 2. Chromobacillus Hansg.

2. Cells short Genus Bacterium Ehrb.

II. Cells encysted Family Myconostocaceae Hansg.

One genus only Genus Myconostoc Cohn

C. Cells spherical Order III. Sphaerobacteria

One family only Family Mycococcaceae

a. Cells encysted Subfamily Cystococcaceae Hansg.

1. Cells irregularly grouped.

a. Each cell or each group of a small number of cells in common

cyst Genus Hyalococcus Schroter

b. As (a), but with many -layered cysts.

Genus Leu^ocystis. Schroter

c. Cell families of very numerous individuals in a common cyst.

Genus Ascococcus Billroth

2. Cells regularly grouped.

a. Cells in chains, encapsulated.

Genus Leuconostoc Van Tieghem

b. Cells in twos and fours, in many layered capsules. Cells

elongate Genus Mycoihece. Hansg.

Metschnikoff (1888) suggested the generic name Sclerothrix for the
acid fast bacteria of the type of the bacillus of tuberculosis. Evidently
he was not aware of the previous use of this name by Kuetzing (1849)
for a genus of algae.

Bollinger (1888) suggested the name Botryomyces as a designation
for the genus of cocci found in the socalled botryomycomata of the horse.
In this year Gamaleia used the name Coccobacillus avicidus for the
organism of chicken cholera.

Beijerinck (1889) proposed the generic designation Photohacterium
to include all of the photogenic forms. This is perhaps the first genus
of bacteria proposed based upon a physiologic character. Frank (1889)
used Rhizobium as the generic name for the bacteria found in the root
nodules of leguminous plants. Spirohacillus was named by Metschnikoff
in the same year.

Probably the most elaborate classification of bacteria based entirely
upon morphologic characters is that of De Toni and Trevisan (1889)
published in Saccardo's.Sylloge Fungorum. ]Many new genera were

40 GENERAL SYSTEMATIC BACTERIOLOGY

recognized, and specific descriptions given of over 650 species. Many
of the species and even some of the genera cannot at present be identi-
fied with certainty, but this classification has nevertheless been entirely
too much ignored by bacteriologists.

De Toni and Trevisan's Classification of Bacteria (1889)
Key to Subfamilies of Schizomycetaceae Naeg.

1. Three stages of development, filaments, rods, and cocci. Filaments (in the

primary stage) sheathed or sheathless, usually with base and apex differenti-
ated, attached or radiating from a central point, rarely free. Rods and cocci
included in the filaments I. Trichogenae Trev.

2. Three stages of development, individual rods, filaments and cocci. Rods

(in the primary stage) forming filaments and cocci; filaments (2" stage)
never sheathed, nor with distinct base, nor fixed, nor radiating from a central
point, formed by single bacilli remaining attached, due to imperfect division.

II. Baculogenae Trev.

3. One stage only, cells spherical III. Coccogenae Trev.

Key to Tribes and Genera of the Trichogenae Trev.

a. Spores (arthrospores) produced in special parts of the filaments (pseudo-
sporangia) Tribe I. Crenotriceae Trev.

Filaments sheathed unbranched Crenothrix Cohn

aa. Spores (arthrospores) produced in normal filaments:

b. Filaments pseudoramose. . .Tribe II. Cladotriceae Trev.
c. Filaments sheathed:

d. Filaments subequal from base to apex. Arthrospores
numerous, dividing in three directions of space.

Sphaerotilus Kuetz
dd. Filaments from base to apex more and more thickened.
Arthrospores formed, dividing only transversely.

Cladothrix Cohn
cc. Filaments not sheathed. Arthrospores coccus-shaped, division

transverse only Nocardia Trev.

bb. Filaments unbranched. . . .Tribe III. Kurthieae Trev.

c. Arthrospores rod shaped Detoniella Trev.

cc. Arthrospores cocci:

d. Filaments fixed at base in zoogloeal masses.

Rasmussenia Trev.

dd. Filaments free Kurthia Trev.

aaa. Spores absent, at least never detected. Filaments unbranched.

Tribe IV. Leptotricheae Trev.
b. Filaments sheathed. Base and tip unequal. Rod-shaped gonidia.

Leptotrichia Trev.
bb. Filaments, not sheathed, equal, no rod gonidia.

GENERAL SYSTEMATIC BACTERIOLOGY 41

c. Filaments fixed. Cell division transverse and longitudinal.

Phragmidiothrix Engler.
cc. Filaments free, division transverse only.

Beggiatoa Trev.

Key to Tribes and Genera of the Subfamily Baculogenae Trev.

a. Bacilli and cocci naked, never with a tegument.

Tribe I. Bacilleae Trev.
b. Producing endospores:

c. Division longitudinal .. Subtribe I. Pasteurieae Trev.

One genus only Pasteuria Metch.

cc. Divisions transverse:

d. Rods united in a reticulate coenobium:

Subtribe II. Thiodictyeae

One genus only Thiodictyon Winogradsky

dd. Rods not united in reticulate coenobium.

e. Rods straight or slightly bent, never spiral.
Subtribe III. Eubacilleae Trev.
f . Spores not greater in diameter than normal vegeta-
tive rods,
g. Spores forming in unchanged rods :

h. Plasma uniformly diffused in rods:
i. Rods fusiform.

Mantagazzaea Trev.
ii. Rods cylindrical or cylindraceous.
Bacillus Cohn
hh. Plasma bipolar in distribution.
Pasteurella Trev.
gg. Spores with special integuments, cells be-
coming ellipsoid-fusiform :

Clostridium Praz.
ff . Spores greater in diameter than the normal vegeta-
tive rods.

g. Spores median in unchanged rods.
Cornilia Trev.
gg. Spores apical in clavate rods.
Vibrio Zopf.
ee. Rods spirally bent.

Subtribe IV. Spirilleae Trev.
f. Rods circular in cross section.

Spirillum Ehr.
ff. Rods compressed in cross section.

Spiromonas Perty
bb. Producing arthrospores :

c. Cylindrical, straight or slightly curved. Filaments undulate —
flexuous or irregularly pseudospiral.

Pacinia Trev.

42 GEXER-Ui SYSTEMATIC BACTERIOLOGY

cc. Rods ellipsoidal, straight, filaments never pseudospLral.

Bacterium Ehr.
aa. Bacilli and cocci surrounded by a special membranous-gelatinous capsule.

Tribe Klebsielleae Trev.
b. Bacilli straight or curved, never true spirals.

Subtribe Euklebsielleae Trev.

c. Capsvde repeatedly ramose Winogradskya Trev.

cc. Capsule simple, never ramose.

d. Plasma uniformly diffused. . . .Klebsiella Trev.

dd. Plasma condensed at poles Dicoccia Trev.

bb. Rods spirally twisted Subtribe Myconostoceae Trev.

One genus only Myconostoc Cohn

Anhang Cysiobacter.

Key to Tribes and Genera of Subfamily Coccogenae

a. Cocci associated in families in bladder-like gelatinous masses or cysts:

Tribe Ascococceae Trev.
b. Cocci separated in mucus of the matrix.

c. Cocci destitute of special cysts, in families in common cysts.
Subtribe Euascocceae
d. Cocci numerous, associated in large families:
e. Cysts homogeneous, not lamellose.

f. Families at first solid, then irregularly clathrate.
Division at first in three directions, then in two

directions Latnprocystis Sehroet.

ff . Families in solid mass, cocci dividing in one direc-
tion Ascococcus Cohn

ee. Cysts lamellose. Solid colonies. Cocci divide in three

planes Bollingera Trev.

dd. Cocci not numerous, associated in small families:

e. Cysts many layered. Division in three directions.

Leucocystis Sehroet.
ee. Cysts homogeneous, not lamellose:

f. Cocci all in periphery. Cocci divide at first in
three directions in two.

Cenomesia Trev.
ff. Cocci few and scattered. Divide in one direction.

Thiothece Winogr.
fff. Cocci in solid families, cocci divide in three direc-
tions Thiocystis Winogr.

"CO. Cocci borne in special cysts. Common cysts absent.

Subtribe Gaffkyeae Trev.
d. Cysts broad, persistent, numerous in conglobate heap,
interior solid, densely aggregated.

Chlamydatomus Trev.
dd. Cysts tenuous, at length breaking apart, solitary, never
associated in heaps Gaffkya Trev.

GENERAL SYSTEMATIC BACTERIOLOGY 43

bb. Cocci in mucoid matrix loosely joined in a plasmic filamentous series.
Cysts very tenuous, at length breaking apart. Special cysts none.
Subtribe Amoebobacteriae Trev.

One genus only Amoebobacter Winogr.

aa. Cocci in families of single or many layers, joined by mucus more or less
conspicuous. No cysts, endospores small, appearing in cocci.

Tribe. Sarcineae Trev.
b. Cocci heaped up closely in firm mucous matrix.

c. Cocci in solid irregular heaped families without order, densely
associated. Cocci divide in one direction.

Thiopolycocc^is Winogr.
cc. Cocci closely associated in regular cubical families, dividing in

three directions *Samna Goodsir

bb. Cocci grouped loosely in mucous matrix.

c. Cocci in fours in one layered families, in firm mucus, forming
parallelograms, loosely associated. Division in two planes.

Lampropedia Schroet
cc. Cocci few in irregular families in firm mucoid membranes, pe-
riphery amorphous, associated without regular order. Divide

in three directions Thiocapsa Winogr.

ccc. Cocci in fours in small regular colonies, one layered, tenuous,
amorphous, scarcely breaking apart, loosely associated. Divide
in two planes. Pediococcus Lindner.

aaa. Cocci in moniliform chains. Arthrospores large in the filaments or on apex.

Tribe III. Streplococceae Trev.
b. Filaments produced in a membranous, gelatinous capsule :

c. Capsules large, broad, lamellose.. . .Leuconostoc Van Tiegh.
cc. Capsules close, tenuous, not lamellose.

Schuetzia Trev.

bb. Filaments in a cylindrical sheath Perroncitoa Trev.

bbb. Filaments naked:

c. Pseudodichotomous. Arthrospores at tip of filaments.

Babesia Trev.
cc. Simple. Arthrospores included in filaments.

Streptococcus Billroth
emended Zopf.
4a. Cocci not in cysts, capsules or sheaths, nor in chains, with endospores.

Tribe IV. Micrococceae Trev.

b. Cocci in pairs Neisseria Trev.

bb. Cocci associated in botryoid masses. . ..Staphylococcus Ogston
bbb. Cocci solitary or associated in amorphous zoogloeal masses.

Micrococcus (Hallier) Cohn

Hansgirg (1890) described two new bacterial genera which have been
uniformly ignored by subsequent writers. They are Mycacanthococcus
and Mycotetraedron, both from wine cellars.

Baumgarten (1890) ignored the recognized rules of nomenclature in
the following classification:

44 GENERAL SYSTEMATIC BACTERIOLOGY

Baumgarten's Classification of Bacteria (1890)

A. Species relatively monomorphic.

I. Cells spherical Genus Kokkus

a. Cells in pairs Subgenus Diplokokkus

b. Cells in chains Subgenus Streptokokkus

c. Cells in tabular masses. . .Subgenus M crista or Merismopedia

d. Cells in regular packets . .Subgenus Sarcina

e. Cells in irregular masses . Subgenus Mikrokokkus
II. Cells rod shaped. Many species with spores.

Genus Bacillus

III. Cells spiral Genus Spirillum

Subgenera Subgenus Vibrio

Subgenus Spirillum
Subgenus Spirochaete

B. Species relatively pleomorphic.

I. Rods and spirals. Proteus types.

Genus Spirulina
II. Long filaments.

a. Unbranched Genus Leptothrix

Subgenera Subgenus Leptothrix

Beggiatoa

Crenothrix

Phragmidiothrix

b. Branched Genus Cladothrix

The Comil-Babes (1890) classification is another example of the
carelessness in the definition of genera frequently to be found among the
writers on medical bacteriology. The following outline will give the
principal groups recognized, although generic names not here mentioned
are used in the body of the text.

Comil-Babes' Classification of Bacteria (1890)

Group I. Micrococcus. Cells spherical.

1. Cells in rosary Streptococcus

2. Cells in irregular groups Staphylococcus

3. Cells in firm gelatinous masses. . .Ascococcus

4. Cells in regular packets Sarcina

Group II. Bacteriaceae. Short rods usually, may develop to filaments.

1. Without capsules.

a. Not polymorphic Bacterium

b. Polymorphic Proteus

2. Encapsulated Ascobacterium

Group III. Bacilli. Longer rods, producing spores. Genera Bacillus and Vibrio.
Group IV. Spirobacteria. Cells spiral.

Genera Spirillum, Spirochaete, Leptothrix, Beggiatoa, Streptothrix.

GENERAL SYSTEMATIC BACTERIOLOGY 45

In the same year also appeared the first of the classifications of
bacteria used by Migula (1890). He gave no summarized statement,
but the following outline shows his conception of generic relationships.

Migula's First Classification of Bacteria (1890)

A. Cells spherical.

I. Cells falling apart upon division Mikrococcus

II. Cells remaining united in groups.

a. Forming irregular masses Staphylococcus

b. Forming regular groups.

1. Cells in chains Streptococcus

2. Cells in regular packets Sarcina

3. Cells in flat plates, tetrads .... Merismopedia

4. Cells in gelatinous masses Leuconostoc

B. Cells rod shaped.

I. No spores produced Bacterium

II. Spores produced.

a. Cell when sporulating not spindle shaped.

Bacillus

b. Cell when sporulating spindle shaped.

Clostridium

C. Cells spiral.

I. Cells relatively short.

a. Stiff, not flexuous Spirillum

b. Flexuous Vibrio

II. Cells relatively long and flexuous Spirochaete

D. Cells filamentous.

Genera. Beggiatoa, Crenothrix, Cladothrix and Sphaerotilus.

Guignard (1890) named an organism responsible for the formation
of large sUmy masses on rocks on the seashore, Streblothrichia Bornetii.

During the year 1891 at least three generic names were applied to
bacteria as new. These were Micromyces b}^ Gruber for a form of
Actinomyces, Eubacillus by Dangeard for certain green bacteria (con-
taining chlorophyll) and Rhodococcus by Zopf for the red cocci.

Ludwig (1892) outlined the following classification of bacterial
genera. The number of genera recognized is smaller than those of some
previous authors, but in some respects it represents a real advance.

Ludwig's Classification of the Bacteria (1892)

I. Cocci, with spherical non-motile cells, without endospores, or with a single
endospore in the cell:
A. Not embedded in slime :

1. Simply or irregularly grouped Micrococcus .,^^^''cC\C. I^

2. Cells in pairs Diplococcus

3. Cells in chains Streptococcus

Xh-

46 GENERAL SYSTEMATIC BACTERIOLOGY

B. Embedded in slime :

1. Single cells Hyalococcus

2. Packets Sarcina

3. Chains Leuconostoc

II. Forming rods, not long filaments:

A. Not embedded in slime :

1. Small elliptical cells Bacterium

2. Small rods with endogenous spores.. Bacillus

3. Spiral:

a. Stiff or rigid Spirillum

b. Long and flexuous Spirochaete

B. Embedded in slime :

1. Cells bent or spiral Myconostoc

2, Straight rods Cystobacter

III, Forming long filaments, usually with a sheath:

A. Unbranched:

1. Non-motile and without inner spore formation.

Leptothrix

2. Non-motile with sheath and inner spore formation.

Crenothrix

3. Motile Beggiatoa

B. Branched:

1. Branches not swollen at tips:

a. Free Cladothrix

b. In slimy sheath Sphaerotilus

2. Branches swollen at tips Actinomyces

Sternberg (1892) used a comparatively simple classification, merging
genera in several cases. His conception of generic names however is
in some cases inconsistent. The following key probably fairly indi-
cates the principal points of difference as recognized by this author:

Sternberg's Classification of Bacteria (1892)

A. Cells spherical.

I. Cells not embedded in gelatinous masses,
a. Cell division in one direction.

1. Cells irregularly grouped Micrococcus

2. Cells in pairs Diplococcus

3. Cells in chains Streptococcus

h. Cell division in two directions, forming tetrads.

Merismopedia
c. Cell division in three planes, forming regular packets.

Sarcina
II. Cells embedded in gelatin.

a. Cells separate in globular or lobulate zoogloeal masses.

Ascococcus
h. Cells solitary or in chains, with a thick gelatinous envelop.

Leuconostoc

GENERAL SYSTEMATIC BACTERIOLOGY 47

B. Rod shaped or filamentous, not spiral, no differentiation between the extremi-

ties of the rods.
I. With or without spores, if the former not fusiform when sporulating.

Bacillus
II. With spores, fusiform Clostridium

C. Curved rods or spiral filaments.

I. Not pleomorphic.

a. Cells not sinuous.

1. Cells rigid, not flexuous Spirillum

2. Cells flexible Vibrio

b. Cells with sinuous motion Spirochaete

D. Cells filamentous, with differentiated base and apex.

I. Without pseudo-branches.

Genera. Leptothrix, Beggiatoa, Crenothrix and Phragmidiothrix.
II. With pseudo-branches Cladothrix

Attention should be called to the merging of all rod-genera (except
Clostridium) into the genus Bacillus. This came in time to be the most
commonly accepted of the medical definitions of the term.

Thaxter (1892) called attention to the existence of a new family
of bacteria which he named the Myxobacteriaceae. The organisms
belonging to this family show a more complex life history than the forms
more commonly studied. The rod shaped cells are associated in a
pseudo-plasmodium which in possession of motility resembles the Plas-
modium of a slime mold. The genera Myxohacter and Alyxococcus
were described.

During the same year the work of Winogradsky (1892) called to at-
tention the important group of soil bacteria which oxidize ammonia
to nitrites and nitrites to nitrates. To his work we owe the generic
names Nitrobader, Nitrosococcus and Nitrosomonas. The genus Nevskia
was also described in the same year by Famintzin (1892) to include
certain rod shaped bacteria which developed peculiar branched or lobed
capsules due to the asymmetric deposition of the gummy material.

During the year 1893 the only generic name proposed was Achroma-
tium by Schewiakoff for an organism of relatively monstrous propor-
tions, which in its content of oxalates (?) simulated in appearance
some of the sulphur bacteria.

Freudenreich (1894) recognized three genera of Coccaceae, Micro-
coccus, Sarcina and Streptococcus with their usual definitions, and in
the Bacteriaceae the genera Bacterium and Bacillus, the latter with en-
dospores, the former without.

48 GENERAL SYSTEMATIC BACTERIOLOGY

Bemhard Fischer (1894) gave the generic name Halihacterium to
nonphosphorescent bacteria from salt water.

The most important contribution of 1894 was the appearance of the
second Migula classification. In practically identical outline but with
some elaboration of subgenera this classification appeared the next year
(1895) under the heading of Schizomycetes in Engler and Prantl's Pflan-
zenfamilien. A key to the families and genera of bacteria as recognized
by Migula is as follows :

Key to the Families of Bacteria. Migula (1894)

I. Cells in free state spherical, not lengthening before division.
Cell division in one, two, or three directions of space.

Family I. Coccaceae
II. Cells short or long cylindric, divide only transversely, and before division
extending to double length:

a. Cells straight, rod shaped, without sheath, non-motile or motile by

means of flagella Family II. Bacteriaceae

b. Cells bent, without sheath.

Family III. Spirillaceae

c. Cells surrounded by a sheath.

Family IV. Chlamydobacteriaceae

d. Cells united into a filament, without sheath, motile by means of an

undulating membrane . . Family V. Beggiatoaceae ■

Key to Genera of the Coccaceae

I. Cells without organs of motion:

a. Division in one direction of space Streptococcus Billr.

b. Division in two directions of space Micrococcus (Hall) Cohn

c. Division in three directions of space. . . .Sarcina Goodsir
II. Cells with organs of motion:

a. Division in two directions of space Planococcus Migula

b. Division in three directions of space Planosarcina Migula

Key to the Genera of Bacteriaceae

I. Cells without organs of motion Bacterium Ehr. emend.

II. Cells with flagella:

a. Flagella over entire cell body Bacillus Cohn emend,

b. Flagella polar Pseudomonas Migula

Key to the Genera of the Spirillaceae

I. Cells stiff, not bending like a snake:

a. Cells non-motile Spirosoma Migula

GENERAL SYSTEMATIC BACTERIOLOGY 49

b. Cells with flagellar

1. Cells with 1, rarely 2 or 3 polar flagella.

Microspira Schroeter

2. Cells with tuft of polar flagella Spirillum Ehr.

II. Cells flexuous Spirochaeta Ehr.

Key to the Genera of Chlamydobacteriaceae

I. Cells contents without sulfur granules:

a. Cell filaments unbranched:

1. Cell division continually in one direction of space.

Streptothrix Cohn emend.

2. Cell division before conidia formation in 3 directions of space.

X. Cells surrounded by a very delicate, scarcely visible sheath

(marine) Phragmidiothrix Engler

XX. Sheaths definitely recognizable (fresh water).

Crenothrix Cohn

b. Cell filaments branched Cladothrix Cohn

II. Cell contents with sulfur granules Thiothrix Winogr.

Key to the Genera of the Beggiatoaceae
One genus only Beggiatoa Trev.

It will be noted that in Migula's classification emphasis is put largely
upon the shape of the cell, motility and the distribution of flagella on
the bacterial cells. Spores are not regarded as useful in the differentia-
tion of genera. Neither the sulfur bacteria nor the Myxobacteria are
recognized as distinct groups.

In 1895 appeared the first classification of Alfred Fischer. The
principal differential characteristic wUl be noted in the family Bact-
eriaceae which is divided into sixteen genera based upon cell form, spore
production, and location of tjie flagella. No species were known for
several of the genera which he included. The classification of this
family follows:

Fischer's Classification of Bacteria (1895)
Key to Genera of Bacteriaceae

I. Family Bacillel. Non-flagellate.

a. Producing endospores.

1. Spore bearing rod cylindric Bacillus

2. Spore bearing rod spindle shaped. . .Paracloster

3. Spore bearing rod clavate Paraplectrum

b. Producing arthrospores Arthrobacter

II. Family Bactriniel. One polar flagellum.

a. Producing endospores.

1. Spore bearing rod cylindric Bactrinium

50 GENERAL SYSTEMATIC BACTERIOLOGY

2. Spore bearing rod spindle shaped . . . Clostrinium

3. Spore bearing rod clavate Plectrinium

h. Producing arthrospores Arthrobactrinum

III. Family Bactrillei. With polar tuft of flagella.

a. Producing endospores.

1. Spore bearing rod cylindric Bactrillum

2. Spore bearing rod spindle shaped. . .Clostrillum

3. Spore bearing rod clavate Plectrillum

b. Producing arthrospores Arthrobactrillum

IV. Family Bactridiel. With diffuse flagella.

a. Producing endospores.

1. Spore bearing rod cylindric Bactridium

2. Spore bearing rod spindle shaped. . .Clostridium

3. Spore bearing rod clavate:

(a) Single spored Plectridium

(b) With two spores Diplectridium

b. Producing arthrospores Arthrobactridium

The year 1896 was notable in the history of bacterial classification
for the appearance of the scheme of Lehmann and Neumann. The
outlines of classification of Migula, Fischer, and Lehmann and Neumann
constitute the bases upon which practically all of the systematic work
of the bacteriologists was built during the next two decades. Lehmann
and Neumann separated from the true bacteria the bacteria-like
Hyphomycetes and the filamentous water or algal bacteria. A key to
the families and genera of the true bacteria is as follows :

Classification of Lehmann and Neimiann (1896)
Bacteria or Schizomycetes

Small cells (almost) always free of chlorophyll, unbranched. Diameter usually
not more than 2/i, rarely 3-o/x. Spherical, elongate or spiral, without organs other
than flagella. Vegetative division usually transverse, very rarely longitudinal.

I. Cells spherical when free Family I. Coccaceae Zopf. emend. Migula.

a. Cells divide only in one direction of space, forming chains if cells remain

united Streptococcus Billroth

b. Cells divide on suitable media in three directions of space, forming

packets Sarcina Goodsir

c. Cells divide irregularly, forming isolated cells or irregular masses.

Micrococcus Cohn
II. Cells at least 1|, usually 2-6 times as long as broad, straight or slightly bent,

never spiral Family II.

Bacteriaceae Zopf. emend. Migula.
a. Without endogenous spores, perhaps often with arthrospores. Rods

usually under O.S-lju diameter Bacterium Cohn emend.

Hueppe.

GENERAL SYSTEMATIC BACTERIOLOGY 51

b. With endogenous spores. Rods often more than 1/* in diameter.

Bacillus Cohn emend.
Hueppe.
III. Cells bent or spiral Family Spirillaceae Migula

a. Cells short, slightly bent, stiff, comma-like, sometimes in spiral cell

groupings, usually with one, rarely two terminal flagella.

Vibrio O. F. Mueller emend. LoflBer

b. Cells long, spirally bent, corkscrew like, stiff usually with a cluster of

polar flagella Spirillum Ehrenb. emend. LoflSer

c. Cells flexuous, long, producing spirally wound filaments. Flagella

unknown. Motile by means of an undulating membrane.

Spirochaete Ehrenb.

As "Anhang I" three genera of the bacteria-like Hyphomycetes
are included. They may be differentiated as follows:

Lehmann and Neumann's Classification of Hyphomycetes (1896)

A. Cultures showing ordinary bacterial character, flat or medium. Micro-

scopically rods with swollen ends Corynebacterium L. & N.

B. Cultures on solid media more or less folded, often "cartilaginous".

I. Usually only short slender rods, seldom short branched filaments
without air mycelium and without aerial conidia, acid fast.

Mycobacterium L. & N.
II. Mycelium filaments long, often bent, without sheath, with true branch-
ing. Many species produce conidia on aerial hyphae. Not acid fast.

Oospora Wallroth

The genera of the fission algae are differentiated as follows:

A. Filaments without sheaths.

1. Without sulphur granules Leptothrix

2. With sulphur granules, motile Beggiatoa

B. Filaments with sheaths.

1. Without sulphur granules.

a. Without pseudodichotomous branching.

Crenothrix

b. With pseudodichotomous branching . . Cladothrix

2. With sulphur granules Thiothrix

In many ways this classification of Lehmann and Neumann is one of
the most satisfactory that has been proposed.

During the year 1896 Beijerinck introduced the generic name Grami-
lohacier for anaerobic spore-bearing bacteria of the butyric acid group;
and Forti named an organism from wine Oenohacillus Ahhae.

Alfred Fischer (1897) somewhat modified his earlier classification
in his "Vorlesungen iiber Bakterien." The key to the higher groups
and genera is as follows:

52 GENERAL SYSTEMATIC BACTERIOLOGY

Fischer's Classification of Bacteria (1897)

Order I. Haplobacterinae
Vegetative phase unicellular, spherical, cylindrical, or spirally twisted;
isolated or united in chains or clusters.

Family I. Coccaceae
Vegetative cells spherical
Sub-Family I. Allococcaceae
Planes of fission without definite sequence; no pronounced colonies or growth
forms, cells isolated or in short chains or irregular clusters.

Genus Micrococcus, Cohn. Non-motile. Includes most cocci, the pathological
"staphylococci" etc.

Genus Planococcus, Migula. Motile.

Sub-family II. Homococcaceae
Planes of fission in definite sequence.

Genus Sarcina, Goodsir. Three planes of division at right angles to each
other. Cubical colonies, non-motile.

Genus Planosarcina, Migula. Similar to Sarcina, but monotrichous, and
motile. '

Genus Pediococcus, Lindner. Two planes of fission, alternate and at right
angles.

Genus Streptococcus, Billroth. Planes of fission parallel, giving rise to chains;
the pathological Streptococci and Leuconostoc.

Family 2. Bacillaceae
Vegetative cell straight, cylindrical, ellipsoidal or egg-shaped; very short
forms diflScult to distinguish from cocci. Fission always transverse.

Sub-family I. Bacilleae
Spore-forming ro ds cylindrical, unchanged.
Genus Bacillus, Cohn. Non-motile.

Genus Bactrinium, A. Fischer. Motile, monotrichous, with terminal cilium:
includes provisionally all monotrichous rods whose spores are as yet unknown,
e.g., Bac. pyocyaneum.

Genus Bactrillum, A. Fischer. Motile, with lophotrichous ciliation. Includes
provisionally Bac. cyanogenum, and many other sporeless forms.

Genus Bactridium, A. Fischer. Motile, peritrichous, in some spores as yet
unknown.

Sub-family II. Clostridieae
Rods spindle-shaped during sporulation.

Genus Clostridium, Prazmowski. Motile, peritrichous; includes some of the
but3'ric bacteria. Genera with monotrichous and lophotrichous ciliation are
unknown as yet.

Sub-family III. Plectridieae
Genus Plectridium, A. Fischer. Motile, peritrichous; some butyric bacteria,
the parasite of tetanus and a methane ferment.

Family 3. Spirillaceae
Vegetative cell cylindrical but spirally twisted. Fission always transverse.
Genus Vibrio Miiller and Lofiler. Very slightly curved rods, ''comma" shaped;
motile, monotrichous. Vibrio cholerae asiaticae and numerous other vibrios of
fresh and salt water.

GENERAL SYSTEMATIC BACTERIOLOGY 53

Genus Spirillum, Ehrenberg. Cylindrical cells twisted in an open spiral;
motile, lophotrichous. Spirillum undula, Sp. rubrum.

Genus Spirochaete, Ehrenberg. Cells long and attenuated, spirally twisted
with numerous turns; cilia unknown; the cell membrane is perhaps yielding.
Spirochaete Obermeieri (remittent fever).

Order II. Trichobacterinae
Vegetative phase an unbranched or branched filament or chain of cells, the
individual members of which break off as swarm-spores (gonidia).
Family 1. Trichobacteriaceae

(a) Filaments non-motile, rigid, enclosed in a sheath.

Genus Crenothrix, Cohn. Filaments unbranched and devoid of sulphur
granules.

Genus Thiothrix, Winogradsky. The same, but containing sulphur granules.

Genus Cladothrix, Cohn. Filaments, branched, false dichotomy (includes
Sphaerotilus) .

(b) Filaments motile, with oscillating and gliding movements, and devoid of a
sheath.

Genus Beggiatoa, Trevisan. Containing sulphur.

Chester (189*7) adopted Migula's (1894) classification of Coccaceae,
Bacteriaceae and Spirillaceae, but separated the forms included by
Lehmann and Neumann in their Hyphomycetes, under the family name
Mycohacteriaceae. His characterization of this family and the genera
is as follows:

Chester's Classification of the Mycohacteriaceae (1897)

Cells short or long, cylindrical or clavate-cuneate in form without a sheath
surrounding the chains of individuals. Without endospores, with possibly the
formation of gonidia like bodies. With true dichotomous branching (this forms
an important group standing between the true Bacteriaceae, and the true fungi on
the one hand and Chlamydobacteriaceae on the other).
Order Mycobacteriaceae Chester

A. In cultures possessing the characters of true bacteria. Growth on solid media

smooth, flat spreading. Rods with swollen ends or cuneate or clavate forms.

Corynebacterium Lehm-Neum.

B. Cultures on solid media raised, folded or warty. Generally short slender rods,

rarely short branched. Take the tubercle stain.

Mycobacterium Lehm-Neum.

The following key to the families Chlamydobacteriaceae and Beg-
giatoaceae shows that in the main Chester followed Migula.

Chester's Classification of the families Chlamydobacteriaceae and Beggiotaceae

(1897)

I. Thread-like, composed of individual cells, surrounded by a sheath. Simple
or with true branching. Ordinary vegetative growth by division in only
one direction of space, i.e., at right angles to the longer axis.

54 GENERAL SYSTEMATIC BACTERIOLOGY

A. Cell content without sulfur granules.

Order Chlamydobacteriaceae

1. Filaments unbranched:

a. Cell division only in one direction of space.

Streptothrix Cohn

b. Cell division in gonidia formation in three directions of space,

X. Cells surrounded by a very delicate, hardly discernible

sheath (marine) Phragmidiothrix Engler

XX. Sheath easily discernible (fresh water).

Crenothrix Cohn

2. Filaments branched Cladothrix Cohn

B. Cell contents with sulfur granules Thiothrix Winogradsky

II. Thread-like, without a capsule, but with undulating membrane and as in
Oscillaria, motile cell contents show sulfur granules . Formation of conidia
not certainly known.

Order Beggiatoaceae
A. Threads apparently not septate, septa only faintly visible with
iodine staining. Colorless or faintly rose colored.

Beggiatoa Trev.

During this year (1897) Miyoshi reported three new genera of sul-
phur bacteria from hot sulphur springs, Thioderma, Thiosphaera and
Thiosphaerion. Ellis named a new iron bacterium Spirophyllum and
Meyer one of the bacteria of the B. subtilis group Astasia asterospora.

In this year also Migula published the first volume of his "System
der Bakterien" containing a general discussion of bacterial morphology
and physiology and an outline of the classification of genera essentially
that of 1895.

Hewlett (1898) in his Manual of Bacteriology recognized a small
group only of genera. Of these the following were used in the sense of
Zopf (1885) Micrococcus, Streptococcus, Sarcina, Clostridium, Clado-
thrix, Leptothrix. The genus Bacillus was defined to include all rod
forms, Spirillum all spiral forms and Streptothrix all thread forms.

Chester in 1899 revised his classification of the family Mycohac-
teriaceae to read as follows :

Mycobacteriaceae Chester (1899)

A. Cells in their ordinary form as short cylindrical rods, often bent and

irregularly swollen, clavate or cuneate. At times Y shaped forms or
longer filaments with true branchings. May produce short coccoid

elements, perhaps gonidia Mycobacterium Lehm-Neum

(including, Corynebacterium L. and N.

B. Cells in their ordinary form as long branched filaments. Produce

gonidia-like bodies. Cultures generally have a mouldy appearance

due to the development of aerial hyphae.

Streptothrix Cohn

Oospora Lehmann-Neumann

GENERAL SYSTEMATIC BACTERIOLOGY 55

In this year a peculiar genus of bacteria was described by Jennings
(1899). He used the name Astrohacter to designate an organism which
multipHed by longitudinal fission, forming radial clusters. The or-
ganisms were found only in certain stained preparations; it is not en-
tirely certain that he was not observing an artifact or at least some
organism not bacterial in nature.

Migula (1900) in the second volume of his "System der Bakterien"
considerably increased the scope of his classification by dividing the
Schizomvcetes into two classes which he termed the Eubacteria and
the Thiobacteria, the true bacteria and the sulphur bacteria.

Migula's Classification of Bacteria (1900)

I. Order Eubacteria: Cells without any "Centralkorper" and free from sulfur
and bacteriopurpurin:

A. Cells spherical. Family Coccaceae Zopf emend. Migula

1. Cells non-motile :

a. Division in one direction of space.

Streptococcus Billr.

b. Division in two directions of space.

Micrococcus (Hallier) Cohn

c. Division in three directions of space.

Sarcina Goodsir

2. Cells motile:

a. Division in two directions of space.

Planococcus Migula

b. Division in three directions of space.

Planosarcina Migula

B. Cells straight rods, at least never spiral.

Family Bacteriaceae

1. Non-motile Bacterium

2. Motile:

a. Flagella monotrichous. . . .Pseudomonas Cohn emend. Smith

b. Flagella peritrichous Bacillus Cohn em. Migula

C. Cells spirally wound or representing a portion of a spiral:

1. Non-motile Spirosoma Mig.

a. Not enclosed in gelatin.

Subgenus Euspirosoma Mig.

b. Enclosed in gelatin. .Subgenus Myconostoc

2. Motile:

a. One, two or three polar flagella.

Microspira Schroeter

b. Tuft of polar flagella Spirillum Ehr.

c. Slender and flexuous Spirochaete Ehr.

D. Cells cylindric, united into a sheathed thread.

Family Chlamydobacteriaceae

56 GENERAL SYSTEMATIC BACTERIOLOGY

1. Filaments unbranched.

a. No distinction between base and apex.

Chlamydothrix Migula

b. Filaments enlarged toward tips:

(1) Sheath relatively thick. . .Crenothrix Cohn

(2) Sheath relatively thin .... Phragmidiothrix Engler

2. Filaments branched dichotomously . »Sp/!aero/27us Kiitzing

II. Order Thiobacteria; Cells without a "Centralkorpor" but with sulfur inclu-
sions. Colorless, or rose, red or violet, with bacteriopurpurin.

A. Filamentous, destitute of bacteriopurpurin.

Family Beggiatoaceae

1. Threads attached, non-motile Thiothrix Winogr.

2. Threads free, motile Beggiatoa Trev.

B. Containing bacteriopurpurin.

Family Rhodohacteriaceae

1. Cells united in families. Division of cells in three directions of

space Subfamily Thiocapsaceae

a. Families small compact, enclosed singly or several together

in a cyst. Capable of swarming.

Thiocystis Winogr.

b. Non-swarming, globose cells spread out upon the substratum

in flat families, loosely enveloped in a common gelatin.

Thiocapsa Winogr.

c. Non-swarming cells arranged in packets like Sarcina.

Thiosarcina Winogr.

2. Cells united into families. Division of cells first in three, then in

two, directions of space.

Subfamily Lamprocystaceae
Families first solid, then globose hollow, perforated net.

Lamprocystis Schroeter

C. Cells united into families. Divisions in two directions of space.

Subfamily Thiopediaceae
Families tubular formed of cells arranged in fours.

Thiopedia Winogr.

D. Cells united in families. Division in one direction of space.

Subfamily Amoebobacteriaceae

1. Cells connected by plasma threads. Families amoeboid motile,

Amoebobacter Winogr.

2. Not as "1":

a. Cells arranged in network, united by their ends.

Thiodictyon Winogr.

b. Cells not arranged in network:

(1) Capable of swarming. Cells loosely aggregated in

gelatin Thiothece Winogradsky

(2) Non-motile, cells closely appressed in colony.

Thiopolycoccus Winogr.

E. Cells free, capable of swarming at any time.

Subfamily Chromatiaceae

GENERAL SYSTEMATIC BACTERIOLOGY 67

1. Cells cylindric-elliptic or elliptic. Moderately thick. Polar

flagella Chromatium Perty

2. Cells rod shaped or spindle form, flagella at poles.

Rhabdochromatium Winogr.

3. Cells spirally twisted Thiospirillum

Beijerinck (1900) suggested the generic natne Aerohacter to include
the gram negative lactic acid and gas producing rods of the B. lactis
aerogenes and coli types. Hartleb (1900) designated an organism from
a root nodule as Pseudorhizobium, and Lagerheim named a bacterium
found parasitic upon certain sea weeds, Sarcinastrum.

Chester (1901) in his Manual of Determinative Bacteriology used
the following family and generic keys:

Chester's Key to the families of Bacteria (1901)

I. Cells unbranched, or show only a false branching in Cladothrix:

A. Cells in their free condition globular, becoming slightly elongated

before division. Cell division in one, two, or three directions of
space Coccaceae

B. Cells short or long, cylindrical, straight, curved, or spiral. Without a

sheath surrounding the chain of individuals; motile or non-motile;
endospores present or absent Bacteriaceae

C. Cells surrounded by a sheath, and arranged in elongated filaments.

Chlamydobacteriaceae

D. Cells not surrounded by a sheath, arranged in elongated filaments, and

motile by means of undulating membrane.

Beggiatoaceae
II. Cells short or long, cylindrical or filaments, often clavate; cuneate or irregu-
lar in form. Without endospores, but with the formation of gonidia-like
bodies due to the segmentation of the cells. Without flagella. Division
at right angles to the axis of a rod or filament. Filaments not surrounded
by a sheath as in Chlamydobacteriaceae. With true dichotomous branching.

Mycobacteriaceae

Key to Genera of the Coccaceae

A. Cells without flagella :

1. Division in one direction of space only.

Streptococcus Billroth

2. Division in two directions of space.il/icrococcws Hallier

3. Division in three directions of space.

Sarcina Goodsir

B. Cells with flagella:

1. Division in two directions of s'pa.ce . Planococcus Migula

2. Division in three directions of space.

Planosarcina Migula

58 GENERAL SYSTEMATIC BACTERIOLOGY

Key to the Genera of the Bacteriaceae

A. Flagella absent, endospores present or absent

Bacterium Ehr.

B. Flagella present :

1. Flagella arising from any part of the body, peritrichic

Bacillus Cohn

2. Flagella attached to one or both poles.

Pseudomonas Migula

Key to the Genera of the Spirillaceae

I. Cells stiff, not flexile:

A. Without flagella Spirosoma Migula

B. With flagella.

1. With 1, rarely with 2 or 3 polar flagella.

Microspira Schroeter

2. With a bundle of polar flagella Spirillum Ehr.

II. Cells flexile Spirochaeta Ehr.

Key to the Genera of Mycobacteriaceae

Cells either short or long, cylindrical — clavate — cuneate in form, which at times
may show true branching, or as long-branched mycelial-like filaments. Fila-
ments not surrounded by a sheath as in Chlamydohacteriaceae. Without
endospores, but with the formation of gonidia-like bodies due to a segmentation
of the cells. Division at right angles to the axis of a rod or filament.

A. Cells in their ordinary form short cylindrical rods, often bent and

irregularly swollen, clavate or cuneate. At times Y-shaped forms
or longer filaments with true branchings. May produce short
coccoid elements, perhaps gonidia Mycobacterium (Lehmann-Neu-
mann), including Corynebacterium (Lehmann-Neumann).

B. Cells in their ordinary form as long-branched filaments. Produce

gonidia-like bodies. Cultures generally have a mouldy appearance
due to the development of aerial hyphae. Streptothrix (Cohn);
Oospora (Lehmann-Neumann).

Key to the Genera of Chlamydobacteriaceae,

Filamentous bacteria composed of rod-shaped cells, and surrounded by a distinct
sheath. Division of the cells at right angles to the axis of the filaments. In
Phragmidiothrix and Crenothrix, however, in the formation of gonidia, a division
of the cells in three directions of space takes place. Reproduction by means
of gonidia, which are either motile or non-motile:
I. Cell contents without sulfur granules:
A. Filaments unbranched:

1. Cell division takes place in one direction of space.

Leptothrix

GENERAL SYSTEMATIC BACTERIOLOGY 59

2. Cell division, before the formation of gonidia, takes place in three
directions of space :

a. Filanaents surrounded by a delicate, scarcely discernible

sheath Phragmidiothrix

b. Filaments surrounded bj^ a plainly discernible sheath.

Crenothrix

B, Filaments show false branchings Cladoihrix

II. Cell contents contain sulfur granules Thiothrix

Lehmann and Neumann (1901) in the second edition of the Grimd-
riss replace the designation of the Anhang I Hyphomycetes with the
name Actinomycetes and the generic name Oospora with Actinomyces.
Otherwise the classification remained the same. During this year
the generic name Azotobacter was suggested by Beijerinck for certain
non-sjTnbiotic nitrogen fixing bacteria of the soil. He also used the
name Urococcus as a generic designation of certain urea-hj^drolyzing
cocci. Bongert used Corynethrix to designate an organism associated
with mouse pseudotuberculosis.

Kendall (1902) proposed a revision of the Migula classification by
the addition of certain genera to the family Bacteriaceae. The new
genera were based entirely upon flagella distribution. A key to the
genera recognized by this author follows :

Kendall's Classification of the Bacteria (1902)

A. Coccaceae: Cells spherical in a free state, not elongate in any direction

before division:

1. Non-motile:

a. Cells in chains, planes of fission parallel.

Streptococcus Billr.

b. Planes of fission without definite sequence.

Micrococcus Cohn

c. Planes of fission three, at right angles.

Sarcina Goodsir

2. Motile:

a. As in Micrococcus Planococcus Migula

b. As in Sarcina Planosarcina Migula

B, Bacteriaceae: Cells elongated, cylindrical, cells elongated before

division:

1. Non-motile:

a. Not branching Bacterium Ehr.

b. Branching Mycobacterium Leh.-Neum.

2. Motile:

a. Flagella peritrichic Bacillus Cohn

b. Monotrichic Bactrillius Kendall

60 GENERAL SYSTEMATIC BACTERIOLOGY

c. Lophotrichic Bactrinius Kendall

d. Unknown Bacterius Kendall

C. Spirillaceae: Cells cylindrical, spirally twisted:

1. Cells rigid, non-motile Spirosoma Migula

2. Cells motile:

a. Cell rigid:

(a) with one or two polar flagella.

Microspira Schroeter

(b) Lophotrichic Spirillum Ehr.

b. Cells flexuous Spirochaete. Ehr.

D. Chlamydobacteriaceae: Cells enclosed in a sheath:

1. Cell division always in one plane. . . Streptothrix Cohn

2. Cell division in three planes, very delicate sheath.

Phragmidiothrix Engler

3. As "2", but sheath clearly visible . .Crenothrix Cohn

4. Cells more or less branched Cladothrix Cohn

E. Beggiatoaceae: Cells without a sheath, motility by means of an undulat-

ing membrane. Cells contain sulfur granules

Beggiatoa Trev.

Allan J. Smith (1902) follows the Chester (1901) classification
consistently.

Matzuschita (1902) in his Bakteriologische Diagnostik adopts the
following simple scheme.

Matzuschita's Classification of Bacteria (1902)

Coccaceae: Cells spherical.

1. Cells in chains Streptococcus

2. Cells irregularly grouped Micrococcus

3. Cells in packets Sarcina

Bacillaceae: Rod shaped Bacillus

Spirillaceae: Spiral or bent rods:

Short Vibrio

Longer, relatively thick Spirillum

Long, very slender Spirochaeta

Klocker (translation 1903) in general employed the generic name
applied by the one who first named the organism. He recognizes the
genera Micrococcus, Pediococcus, Sarcina, Bacterium, Bacillus, Ter-
mobacterium, Saccharohacillus, Clostridium and Granulohacier.

The classification used by Alfred Fischer (1903) in the second edition
of his Vorlesungen is given below.

Fischer's Classification of Bacteria (1903)

A. Order I. Haplobacterinae. Vegetative body, one-celled, spherical, cylindri-
cal or spiral ; single or united to unbranched chains and other growth forms :

GENERAL SYSTEMATIC BACTERIOLOGY 61

I. Family I. Coccaceae: Vegetative cells spherical

a. Subfamily, Allococcaceae: Division in three directions of space,

no sharply marked growth form, short chains, masses, in twos
or singly:

1. Non-motile Micrococcus Cohn

2. Motile Planococcus Migula

b. Subfamily Homococcaceae: with definite division sequence for each

genus :

1. Division in three directions of space, forming packets of cells.

(a) Non-motile Sarcina Goodsir

(b) Motile Planosarcina Migula

2. Division in two directions of space, forming fours or plate-

lets Pediococcus Lindner

3. Division walls always parallel, grow in chains, pairs and

singly, no plates or packets. .Streptococcus Billroth

II. Family II. Bacillaceae: Vegetative cells cylindric, ellipsoid, oval,

straight, during rapid multiplication, difficult to differentiate from
cocci.

a. Subfamily Bacilleae: Spore forming rods unchanged, cylindric.

Includes all forms not producing spores:

1. Non-motile Bacillus Cohn

2. Motile.

(a) Monotrichous Bactrinium A. Fischer

(b) Lophotrichous Bactrillum A. Fischer

(c) Peritrichous Bactridium A. Fischer

b. Subfamily Clostridieae : Spore forming rods, spindle shaped:

1. Non-motile Paracloster A. Fischer

2. Motile, peritrichous Clostridium Prazmowski

c. Subfamily Plectridieae: Spore bearing rods, drumstick shaped:

1. Non-motile Paraplectrum A. Fischer

2. Motile, peritrichous Plectridium A. Fischer

III. Family IH. Spirillaceae: Vegetative cells cylindric, but spiral.

a. Slightly curved rods, motile, monotrichous

Vibrio (Miiller-Loeffler)

b. Decidedly spiral in broad turns, motile, lophotrichous.

Spirillum Ehr.

c. Very slender, many turns, flagella unknown, perhaps cell wall

flexile Spirochaete Ehr.

B. Order II. Trichobacterinae: Branched or unbranched cell filaments, whose
segments. are separated off as swarm cells (gonidia) or homogones. One
family: Trichobacteriaceae.
I. Non-motile^ rigid, enclosed in a sheath,
a. Unbranched:

1. Without sulfur inclusions:

(a) Not attached, cylindric gonidia, swarming.

Chlamydothrix Migula

(b) Attached, spherical gonidia not observed to be motile.

Crenothrix Cohn

2. With sulfur granules, attached.

Thio'ihrix Winog.

62 GENERAL SYSTEMATIC BACTERIOLOGY

b. Dichotomously pseudobranched; lophotrichous cylindric gonidia.

Cladothrix Cohn
II. Filaments slowly moving, without sheath. Containing sulphur.

'iaoa Trev.

During this year the name Thiophysa was given by Hinze (1903)
to a new genus of the sulphur bacteria ; and Troili-Petersson named the
lactic acid rods Brachybacierium.

Migula in 1904 again outlined his classification promulgated in
1900 and vigorousl}^ defended it from the criticisms that had been made
against it. New genera described during the year were Hypnococcus
(Bettencourt, Kopke, Renzende and IMendes) for an organism found
associated with sleeping sickness, Clonothrix (Schorler) for one of the
iron bacteria, and Thiobacillus (Beijerinck) for organisms which could
reduce nitrates, oxidize sulphur and utilize CO2 in the manufacture of
plant food.

Winslow and Rogers (1905) as the result of a careful study of many
types and races of the cocci made some rather radical rearrangements
of the groups, and created the new subfamilies Paracoccaceae and
Metacoccaceae. New genera were Aurococcus, Alhococcus and Rhodo-
coccus. This classification was later further elaborated and published
in 1910. A key to the families and genera recognized will be found
under that year.

One of the most comprehensive analyses of the classification of bac-
teria which has been published in English is that of Erwin F. Smith
(1905) in the first volume of his Bacteria in Relation to Plant Diseases.
For his family and generic names he follows Migula (1900) consistently,
except for several genera for which he substitutes older names. The
genus Pseudomonas he concludes is a synonym of Bacterium Cohn.
For Bacterium of the Migula system he proposes Aplanobacter, The
geaus Microspira Schroeter he concludes is a synonym of the older
Vibrio. Furthermore he recognizes as a third order coordinate with
Eubacteria and Thiobacteria the order Myxobacteria. His key to the
genera of the Myxobacteria follows:

Smith's Classification of the Myxobacteria (1905)

III. Order Myxobacteria: Motile rod-like organisms, multiplying by fission,
secreting a gelatinous base, and forming pseudoplasmodium-like aggrega-
tions before passing into a more or less highly developed cyst-producing
resting stage, in which the rods become encysted in groups without modifi-
cation, or may be converted into spore masses.

GENERAL SYSTEMATIC BACTERIOLOGY 63

1. Rods forming free cysts, in which they remain unmodified. Cysts

various, sessile or borne on a more or less highly developed cystophore.

Chondromyces B. and C.

2. Rods forming large rounded cysts, one or more free without gelatinous

matrix raised above the substratum... .Polyangium K.

3. Rods slender, swarming together after a vegetative period to form

definite more or less encysted, sessile or stalked masses of coccus-like
spores Myxococcus Thaxter

Particular attention was called to the group of spirochetes by the
discovery by Schaudinn (1905) of the causal organism of syphilis. It
was first named Spirochaeta, later Vuillemin (1905) proposed Spiro-
nema. This name was invalid under the rules of priority, so Schau-
dinn (1905) proposed Treponema and Stiles and Pfender (1905) a
little later the name Microspironema. Two other new generic names
were proposed during this year, Erythrobacillus by Fortineau for a
red pyogenic rod, and Semidostridium by Maassen for a spore-producing,
gelatin-forming bacterium from sugar vats.

Blanchard (1906) discussed the relationships of the spiral organ-
isms, and concluded that they should be placed in two groups, the plant
forms in the Spirobaderia and the forms more closely related to the
protozoa imder Trypanosomidae. The following key gives the principal
points of differences recognized.

Blanchard's Classification of Spiral Organisms (1906)

I. Spirobacteria, Cohn 1875, Bacteria more or less curved, sometimes the curve
forming only an arc of a circle, at other times forming spirals of several or
many turns. Organisms little or not at all flexible, multiplying by trans-
verse division. Endospores formed in a number of species.

A. Non-motile Spirosoma Migula 1900

B. Motile:

1. Cells rigid, forming a segment of a circle or united into spirals;

1, 2 or 3 polar flagella Vibrio Ehrenberg 1838

2. Cells definitely spiral:

a. With endogenous spores. Flagella not polar.

Spirobacillus Metchnikoff 1889

b. With or without endogenous spores. Flagella polar.

Spirillum Ehrenberg 1838
II. Trypanosomidae Doflein 1901. Flagellum continuous in the form of a spiral
with turns more or less numerous. Organisms flexible, form more or less
fixed, multiplying by longitudinal division. No endogenous spores
Gram — , not cultivable by ordinary means in laboratory:
A. Form constant, greatly elongate:

1, Undulating membrane present, cells flattened.

Spirochaeta 1838 Ehrenberg

64 GENERAL SYSTEMATIC BACTERIOLOGY

2. Undulating membrane absent. Cells round in cross section.

Treponema Schaud.
B. Form changeable, not greatly elongate.

Trypanosoma and Trypanoplasma

New genera named during this year were Rhodocapsa and Rhodothece,
red sulphur bacteria, by Molisch (1906), Actinohacterium by Haass
(1906) and Lipobacter by de Kruyff (1906) for certain lipolytic and fat
oxidizing bacteria.

Lotsy (1907) apparently alone among writers on classification or
bacteria has followed Fischer in his classification of bacteria.

Molisch (1907) in his " Purpurbakterien " created the order Rhodobac-
teria to include all of the forms which contain bacteriopurpurin. Many
new genera of these forms which do not contain sulphur granules are
included. A key to the families and to the subfamilies of the Thior-
rhodaceae and to the genera of the Athiorhodaceae which he gives may be
translated as follows :

Molisch's Key to the Sulphur Bacteria (1907)

Order Rhodobacteria
Bacteria whose cell contents are colored rose, red, violet or carmine by the
presence of bacteriopurpurin, and as far as studied, by bacteriochlorin.

A. Cells have the ability to deposit granules of free sulphur in the cell contents.

Family I. Thiorhodaceae
I. Cells united in families.

a. Division of cells in three directions of space.

Subfamily 1. T hiocapsaceae
h. Division of cells first in three, then in two directions of space.
Subfamily 2. Lamprocystaceae

c. Division of cells in two directions of space.

Subfamily 3. T hiopediaceae

d. Division of cells in one direction of space.

Subfamily 4. Amoebobacteriaceae
II. Cells always swarming.

a. Not capsulated. Subfamily 5. Chromatiaceae

b. Capsulated Subfamily 6. Rhodocapsaceae

B. Cells are unable to deposit free granules of sulphur in the cell contents.

Family II. Athiorhodaceae
I. Cells united into families.

a. Cells rodshaped, embedded many together in a common capsule.

Genus Rhodocystis

b. Cells spherical or short rods, in chains, each chain enclosed in a

capsule Genus Rhodonostoc

II. Cells free.

a. Cells spherical, non-motile.

Genus Rhodococcus

GENERAL SYSTEMATIC BACTERIOLOGY 65

b. Cells straight rods, non-motile.

Genus Rhodobacterium

c. Cells motile rods Genus Rhodobacillus

d. Cells short, bean or comma shaped, monotrichous, actively motile.

Genus Rhodovihrio

e. Cells spiral, actively motile by means of a cluster of polar flagella

Genus Rhodospirillum

This work of Molisch is practically the only work of importance on
these bacteria since the first formulation of description and the group-
ing together of these organisms by Winogradsky.

Other genera of bacteria described in 1907 include Pedioplana, a
motile organism occurring in tetrads, named by Wolff; Thioploca a fila-
mentous sulphur organism related to Beggiatoa, named by Lauterborn;
Myxohacillus, Myxokokkus and Pleimohacterium, OTganisuis producing
gums and slimes in sugar vats, named by Gonnermann ; and Borrelia
for the spirochetes of relapsing fever named by Swellengrebel. The
last named classifies the spiral organisms as follows :

Swellengrebel's Classification of the Spirillaceae (1907)

Cells with rounded tips, constituting any part of a spiral.
I. Subfamily. Spirillaceae. (nov. fam.) Cells are not jflexible. Genera,
Spirillum and Vibrio with diagnoses of Migula.
II. Subfamily. Spirochaetaceae (nov. fam.) Cells are flexible.

a. Cells without cilia, with periplastic appendage well developed and often

with an alveolar structure. Sometimes there is a band of myonemes

in the appendage Spirochaeta Ehrenberg

Type Spirochaeta plicatilis Ehrenb. S. balbianii placed here provision-
ally.

b. Cells with one cilium at one end, sometimes at both extremities, which

is a prolongation of the "calotte," the appendage has been demon-
strated sometimes Treponema Schaudinn

Types (iS. buccalis, Tr. pallidum).

c. Cells with peritrichous cilia Borrelia n. gen.

Type, Sp. gallinarum.

Ellis in 1907 as a result of studies on the iron bacteria came to the
conclusion that they should be separated into two principal groups
in accordance with the following scheme :

Ellis' Grouping of the Iron Bacteria (1907)

I. Reproduction by external abstriction of conidia :
Lepiothrix ochracea
Gallionella ferruginea
Spirophyllum ferrugineum

66 GENERAL SYSTEMATIC BACTERIOLOGY

II. Reproduction by separation of internally produced cells:
Crenothrix polyspora
Cladothrix dichotoma
Clonothrix fusca

The Winslows (1908) presented the final results of their studies on
the Coccaceae. A key to the subfamilies and genera recognized
follows :

Winslows' Classification of the Coccaceae (1908)

Cells spherical. Family Coccaceae
I. Parasites. Growth not abundant (or one species, zooglea-forming sapro-
phytes growth abundant in saccharose media). Generally gram+. Acid
formers Subfamily Paracoccaceae

A. Cells in capsulated pairs. Parasites. Growth very meagre. Inulin

fermented. No pigment.

Diplococcus (Weichselbaum) Winslow and Rogers

B. Cells in chains occuring in masses of zoogloea in sugar refineries.

Aberrant saprophytic forms. Growth abundant in saccharose
media. No pigment Ascococcus (Cohn) Winslow and Rogers

C. Cells in chains. Parasites. Growth meagre. Inulin not fermented.

No pigment Streptococcus (Billroth)

D. Cells in irregular groups Staphylococcus

1. Parasites. Growth fair. Orange pigment.

Aurococcus Winslow and Rogers

2. Parasites. Growth good. White pigment.

Albococcus Winslow and Rogers-
II. Saprophytes. Growth abundant. No zoogloea. Gram— generally. Not
acid formers Subfamily Metacoccaceae

A. Cells in irregular groups. Pigment generally yellow.

Micrococcus (Hallier, Cohn), Winslow & Rogers

B. Cells in packets. Pigment yellow.

Sarcina (Goodsir) Winslow and Rogers

C. Cells in irregular groups or packets, pigment red.

Rhodococcus Winslow and Rogers

Fliigge (1908) in the classification of the pathogenic bacteria given
in his Grundriss der Hygiene (sixth edition) made a distinct contri-
bution to systematic bacteriology in the groupings which he created.
From a strict nomenclatural point of view his terminology was in
many cases technically incorrect, but the groups are very useful.
His classification is as follows :

GENERAL SYSTEMATIC BACTERIOLOGY 67

Fliigge's Classification of the Pathogenic Bacteria

(Lehrbuch der Hygiene, 6th ed., 1907, Quoted in Kolle and Hetch, 3rd ed.

1911, p. 18)
I. Coccaceae: Cells spherical.

A. Family Streptococcus. Grow only in one direction, are Gram +,

non-motile and grow only sparingly on artificial media.

1. Diplococcus type, forms in many media only round or lancet

shaped diplococci, in others (bouillon) short chains. Pathogen:
Diplococcus lanceolatus capsulatus.

2. Streptococcus type. In bouillon, generally forms long chains.

Saprophytes, Streptococcus mesenteroides.

B. Family, Sarcina. Numerous species, in part motile and flagellated,

dividing in three directions of space, forming packets, Gram — on
solid media, growing usually in the form of dry layers, often colored,
often in dust.
Pathogens: None.

C. Family, Micrococcus. Numerous species, of which many are sapro-

phytic, found in dust. Cells divide irregularly in different directions
of space and are often united in bunches of 2, 4, 8 or irregularly:

1. Diplococcus type. Elongated cocci with the long side appressed.

Gram negative.

Pathogens: Micrococcus gonorrhoeae, Micrococcus intracellu-
laris meningitidis, Micrococcus catarrhalis.

2. Tetragenus type. Forms cocci that remain in twos or more, fre-

quently remain in fours.
Pathogen: Micrococcus tetragenus.

3. Staphylococcus type, Spherical. Grows on solid and fluid nutrient

media in regular masses, with white, yellow or orange pigment.
Pathogen: Staphylococcus pyogenes aureus.
II. Bacillaceae. Rod shaped. Not spiral.

A. Family, Bacillus. All rods which produce endogenous spores:

1. Aerobic forms:

a. Hay bacillus group. Relatively large bacilli, widely dis-

tributed, grow well on solid and liquid media, on the
latter with membrane formation. Usually motile. Non-
pathogens.

b. Anthrax group. As "a" but non-motile and pathogenic.

2. Anaerobic forms. Includes all the spore bearing types of butyric

acid bacteria.

Pathogens: B. botulinus, Bacillus of blackleg, of edema, of
tetanus.

B. Family Bacterium. All rods that produce no spores:

1. Fluorescent, phosphorescent, and pigment producing forms.

Gram negative, may or may not liquefy gelatin.

2. Colon bacillus group, possesses flagella, more or less motile. Gram

negative.

Pathogens: Bad. typhi, and Bact. paratyphi.

68 GENERAL SYSTEMATIC BACTERIOLOGY

3. Bad. aerogenes group, very near B. colt (but non-motile?).

Pathogen: Bad. dysenteriae.

4. Plague and septicemia group. Non-motile, polar staining. Gram

negative, do not liquefy gelatin.
Pathogen: Bad. pestis.

5. Influenza group. Very small. Gram—, growing only on media

containing hemoglobin.
Pathogen : Bad. influenzae

6. Swine erysipelas group. Very small rods, do not liquefy gelatin.

Gram positive.

Pathogen: Bad. Rhusiopathiae, Rabbit septicemia.

7. Glanders group. Very slender rod. Gram negative.

Pathogen: Bad. mallei.

8. Diphtheria group. Gram positive. Tendency to the production

of club shaped involution forms and to granular disintegration.
Pathogen, Bad. diphtheriae, Bad. xeroseos.

9. Acid fast group. Producing slimy wrinkled layers on the surface

of solid and liquid media. Gram positive and acid fast.
Pathogen: Bad. tuberculosis.
III. Spirillaceae: Cells spiral.

A. Family Vibrio. All comma-shaped, bent, fission fungi with polar

flagella. Often united to spirals. Gram negative.
Pathogen: ]'ibrio cholerae asiaticae.

B. Family Spirillum. Several corkscrew turns. Polar flagella. Many

saprophytes.
Pathogens: None known.

The classification of the Trichomycetes or thread bacteria suggested
by Jordan (1908) is worthy of note. He diagnosed the genera as
follows :

Jordan's Classification of the Trichomycetes (1908)

1. Filaments unbranched Leptothrix

2. Filaments with pseudobranches Cladothrix

3. Filaments with true branches.

a. Reproductive elements, spores observed . . . Nocardia

b. No spores observed Actinomyces

Conn (1909) suggested the following classification:

Conn's Classification of Bacteria (1909)

Spherical Bacteria:

Dividing in one plane, so as to form chains. Streptococcus.

Dividing in two planes, and not forming chains. Micrococcus.

Dividing in three planes, and forming cubical masses, Sarcina.
Rod Shaped Bacteria:

With flagella, and consequently motile, Bacillus.

GENERAL SYSTEMATIC BACTERIOLOGY 69

Without flagella and consequently non-motile, Bacterium.
With a single flagellum, Pseudomonas.
Spiral Bacteria: Spirillum.

Higher Bacteria: {Cladothrix, Leptothrix, Streptothrix, Actinomyces)
The genus Bacillus is further divided as follows:

Bacilli with one flagellum are named Monotrichic Bacilli or Pseudomonas.
Bacilli with one flagellum at each end, Microsporon.
Bacilli with a tuft of flagella at one end are called Lophotrichic Bacilli.
Bacilli with flagella over the whole body are called Peritrichic Bacilli.

Orla- Jensen in 1909 proposed a totally new classification of bac-
teria. He divided the bacteria into two orders based upon primitive
or advanced characteristics, distribution of flagella, etc. In many cases
his published descriptions of genera are not very clear, and the con-
struction of a key for the differentiation of the forms is correspond-
ingly difficult. The following key will indicate differences between
most of the genera described.

Orla- Jensen's Classification of Bacteria (1909)

Key to Orders and Families

I. Cells spherical, rod-shaped or spiral. Endospores formed only in a few
sulfur-free spirilla. When motile, mono-or lophotrichous. Tj-pically
water bacteria. Secure energy almost exclusively by oxidative processes.
Many develop poorly on laboratory media because organic substances are
present in too concentrated a form.

Order I. Cephalotrichinae
A. Bacteria not in thread like filaments, no tendency to branch or produce
mycelial growth:

1. Bacteria not containing sulfur or bacteriopurpurin:

a. Obligate aerobes, oxidizing carbon, hydrogen, or nitrogen

compounds without production of noteworthy amounts of
unoxidized split products.

Family 1. Oxydohacteriaceae

b. Luminous and fluorescent bacteria.

Family 6. Luminibacteriaceae

c. Active reducing organisms, facultative, all spiral forms re-

ducing sulfates.

Family 7. Reducibacteriaceae

2. Bacteria containing sulfur or bacteriopurpurin:

a. Containing no bacteriopurpurin.

Family 3. Thiobacteriaceae
h. Containing bacteriopurpurin.

Family 4. Rhodobacteriaceae
B. Bacteria tending to branch, to form filaments or to develop a
mycelium.

70 GENERAL SYSTEMATIC BACTERIOLOGY

1. Not typically water forms. Cells tending to branch and to form

branching hyphae. Not forming filaments usually.
Family 2. Actinomycetes

2. Typically water forms. Cells not tending to form mycelium.

Typically filamentous.

Family 5. Trichobacteriaceae
II. Cells spherical or rod shaped, never spiral. Either peritrichous or non-
motile. Not typically the water bacteria. Do not secure growth energy
solely by oxidative processes.

Order II. Peritrichinae

A. Typically not obligate anaerobic or microaerophilic.

1. Usually bringing about transformation in carbohydrates with the

development of acids.

Family 1. Acidobacteriaceae

2. Usually bringing about an alkaline reaction by the development

of ammonia Family 2. Alkalibacteriaceae

B. Typically obligate anaerobic or microaerophilic.

1. Acting largely upon carbohydrates, developing acids, particularly

butyric acid Family 3. Butyribacteriaceae

2. Acting largely upon proteins, bringing about putrefactive changes.

Family 4. Putribacieriaceae

Order I. Cephalotrichinae

Key to the Genera of Family I. Oxydobacteriaceae

I. Not oxidizing nitrogen compounds nor fixing free nitrogen:

A. Oxidizing methane to CO2 and H2O Mcthanomonas

B. Oxidizing CO to CO2 Carboxydomonas

C. Oxidizing H2 to H2O Hydrogenomonas

D. Oxidizing alcohol to acetic acid Acetimonas

II. Oxidizing ammonia or nitrites:

A. Oxidizing ammonia Nitrosomonns

B. Oxidizing nitrites Nitromonas

III. Fixing atmospheric nitrogen Azotobacter

Key to the Genera of Family II. Actinomycetes

I. Not producing a much branched mycelium, individual cells only branching:

A. Symbiotic in the nodules of legumes Rhizomonas

B. Not symbiotic. Parasites in mammals:

1. Not acid fast Corynemonas

2. Acid fast Mycomonas

II. Producing a much branched mycelium Actinomyces

Key to the genera of Family III. Thiobacteriaceae

I. Cells not spiral:

A. Cells rod-shaped, or not spherical:

1. Autotrophic, rod-shaped Sidphomonas

2. Not autotrophic, oval (?) Thiomonas

GENERAL SYSTEMATIC BACTERIOLOGY 71

B. Cells spherical Thiococcus

II. Cells spherical Thiospirillnm

Key to the Genera of Family IV. Rhodobacteriaceae

Uses the following genera with the same meanings as Winogradsky or Molisch.
Rhodomonas (Chromaiium).
Rhabdomonas (Rhabdochromati urn) .
Rhododictyon {Thiodictyon).
Amoeboinonas {Amocbobacter) .
Rhodothece {Thiothece).
Rhodopolycoccns (Thiopolycoccus) .
Rhodococcus (Thiopedia).
Lamprocystis.
Rhodocystis (Thiocystis).
Rhodocapsa {Thiocapsa).
Rhodosarcina {Thiosarcdna).
Rhodospirillum ( Th lospirillum) .

Key to the Genera of Family V. Trichobacteriaceae

I. Not containing sulfur granules:

A. Branched (with pseudobranches) Cladothrix

B. Not Branched

1. Not spiral:

a. Not attached Lepfothrix

b. Attached Crenothrix

2. Spiral:

a. Slender and flexuous Spirochaeta

b. Flattened Spirophyllum

II. Containing sulfur granules:

A. Not attached. Motile Beggiatoa

B. Attached Thiothrix

Key to the Genera of Family YI. Lximinobacleriaceae

I. Cells not spiral:

A. Cells rod-shaped:

1. Active denitrifiers Denitromonas

2. Active liquefiers Liquidomonas

B. Cells spherical:

1. Liquefying gelatin Liqiiidococcus

2. Not liquefying gelatin SoUdococcus

II. Cells bent or spiral Liquidovibrio

Key to the Genera of Family VII. Reducibacteriaceae

I. Short spiral. Not liquefying gelatin Solidovibrio

II. Longer spirals Spirillum

72 GENERAL SYSTEMATIC BACTERIOLOGY

Order II. Peritrichinae
Key to Genera of Family I. Acidobacteriaceae

I. Active denitrifying forms Denilrobacterium

II. Not as in I:

A. Rod shaped:

1. Organisms of the B. colt group Bacterium

2. Gram + lactic acid forms Caseobacterium

3. Producing propionic acid Propionibacteri%im

B. Spherical:

1. In chains Streptococcus

2. Irregularly grouped Micrococcus

3. In packets Sarcina

Key to the Genera of Family II. Alkalibacteriaceae

I. Organisms of the Proteus type Liquidobacterium

II. Organisms of the B. subtilis type Bacillus

III. Producing ammonia from urea Urobacillus

Key to the Genera of Family III. Butyribacteriaceae

I. Acting primarily upon sugars, forming butyric acid.

Butyribacillus

II. Acting primarily upon pectin Pectobacillus

III. Acting primarily upon cellulose Cellulobacillus

Key to the Genera of Family IV. Putribacteriaceae

I. Not producing an ectotoxin Putribacillus

II. Producing an ectotoxin Botulobacillus

It will be noted that Orla- Jensen has created a considerable number
of generic names, many times substituting new names for older and
apparently perfectly valid terms.

Among the new genera described in 1909 by other authors were
Hillhousia a giant sulphur organism named hj West and Griffiths,
Siderocapsa, a capsulated epiphytic coccus growing in water contain-
ing iron and with iron oxid deposition in the capsule, named by Molisch,
and Erysipelothrix an organism of the general type of the bacterium of
swine erysipelas named by Rosenbach.

Molisch (1910) in his book "Die Eisenbakterien " recognizes the
genera and species separated by the following key.

Molisch (1910) Classification of the Iron Bacteria

A. Filamentous bacteria.

I. Filaments always unbranched.

a. With brown attaching disks Chlamydothrix sideropoiis

h. Not as "a."

GENERAL SYSTEMATIC BACTERIOLOGY 73

1. With definite sheath, often broader toward end. Not spirally

wound Crenothrix polyspora

2. Without definite sheath. Spirally wound.

Gallionella ferruginea
II. Filaments unbranched or pseudodichotomously branched,
a. Swarm cells developed.

1. Regularly pseudodichotomously branched, usually colorless.

Cladothrix dichotoma

2. Usually unbranched, usually encrusted with iron

Chlamydothrix ochracea

h. Only non-motile gonidia Clonothrix fusca

B. Capsule bacteria.

I. Capsule with only a few (1-8) cells Siderocapsa Treubii

II. Capsule with 1-100 cells Siderocapsa major

Among the new generic names of bacteria proposed in 1910 were
the following: Fusiformis for the fusiform bacteria of the throat
named by Hoelling, Asierococcus for the very minute organism re-
sponsible for the disease pleuropneumonia in cattle, named by Borrel
et al, Actinobacillus by Brumpt for the causal organism of actino-
bacillosis of cattle, Nodofolium for one of the thread iron bacteria
named by Ellis and Cristispira given by Gross as designation of the
spiral "crested" organism from the crystalline styles of certain classes
of mussels.

Dobell (1911) included the spirochetes in the group Spirochaetoidia,
using the following generic differences for the three genera recognized.
He emphasizes that this group of Protista should be included neither
with the bacteria or protozoa.

Spirochaetoidia

1. Free living forms, fresh water or marine Spirochaeta Ehr.

2. Parasitic in animals (Vertebrates and Invertebrates).

Treponema Schaudinn

3. Parasitic in Lamellibranchia Cristispira Gross

In Doflein's Lehrbuch der Protozoenkunde (1911) the same problem
is handled by considering Spirochaeta as a generic name which includes
aU forms, and regarding Spirochaeta, Cristispira and Treponema as
the component subgenera. Gross in this year added the genus Sap-
rospira to this group. He included it in the free living marine types.

Frost in Marshall's Microbiology (1911) used Migula's (1900) scheme
of classification in its entirety. Heim in the 4th edition of his Lehr-
buch der Backteriologie gives a verj'- simple classification suitable par-
ticularly for the pathogenic bacteria.

74 GENERAL SYSTEMATIC BACTERIOLOGY

Heim's Classification of Bacteria (1911)

I. Coccaceae. Cells spherical:

A. Division in one direction of space Streptococcus

B. Division in different directions, no chains or packets.

Micrococcus

C. Dividing in three planes, forming packets.

Sarcina
II. Bacteriaceae, Rod-shaped:

A. Without spores Bacterium

B. With spores Bacillus

III. Spirillaceae. Cells spiral:

A. Rigid spirals or sections of spirals Spirillum and Vibrio

B. Flexuous, Spirals Spirochaete

Kolle and Hetsch (1911) differentiate the bacteria into the fission
fungi consisting of cocci, bacilli and spirilla and the fission algae
including the sulphur bacteria, the iron bacteria and the Strep-
tothricaceae.

Bosanquet (1911) in his book on Spirochaetes places all in the genus
Spirochaeta. During this year two other bacterial generic names
were proposed: Paraspirillum for a flexile spindle formed spiral or-
ganism in water (Dobell) and Cohnistreptothrix for organisms of the
type of Streptothrix Foersteri of Cohn (Pinoy and JVIorax).

Schneider (1912) follows the classification used by Chester (1901).
Benecke (1912) gives one of the most complete of the recent systems
of bacterial classification. The orders and families recognized are
shown in the following scheme:

Benecke's Classification of Bacteria (1912)

A. Comparativelj' simple organisms, not growing as sheathed filaments, usually
as single cells or colonies . .Order I. II aplohacterinae
I. Cells not forming a pseudoplasmodium.

a. Cells not tending to branch or form a mycelium.

1. Without bacteriopurpurin.

(a) Cells spherical.

Family I. Coccaceae

(b) Cells elongate.

(1) Cells straight.

Family II. Bacilla^eae

(2) Cells spiral.

Family III. Spirillaceae

2. With bacteriopurpurin.

Family IV. Rhodobacteriaceae

b. Cells tending to branch or form a mycelium.

Family V. Mycobacteriaceae

GENERAL SYSTEMATIC BACTERIOLOGY 75

II. Cells in vegetative stage forming a pseudoplasmodium.

Family IV. Myxobacteriaceae
B. Cells in filaments, frequently sheathed.

Order II. Desmobacterineae
One family only Family VII. Desmobacteriaceae

While no new genera are described, a larger number of genera are
included in several of the families than by most other writers.

Engler (1912) in the seventh edition of his syllabus gives the fol-
lowing outline of bacterial classification:

Engler's Classification of Bacteria (1912)

Schizomycetes
I, Order Eubacteria. Cells without sulfur and bacteriopurpurin:

A. Family, Bacteriaceae: Cells very small, cylindric, straight or slightly

bent:

1. Without flagella Bacterium

2. With flagella:

a. Peritrichous Bacillus

h. Polar Pse\ido7nonas

B. Family, Spirillaceae: Spiral cells:

1. Cells stiff, not serpentine:

a. Non-motile Spirosoma

h. Motile:

(1) With 1, 2, or 3 polar flagella.

Microspira

(2) With bunch of polar flagella.

Spirillmn

2. Cells serpentine Spirochaete

C. Family, Phycobacteriaceae: {Chlamydobacteriaceae) Filamentous, sur-

rounded by a more or less definite sheath and dividing seldom in
three directions. Multiplication by conidia.

Genera: Phragmidiothrix, Chlamydothrix, Gallionella, Crenothrix,
Clonothrix, Sphaerotilus (Cladothrix) .

D. Family, Actinomycetaceae : Filamentous colonies with true branching,

radiating, non-motile. Filaments dividing up into oidia.
One genus Actinomyces

E. Family, Coccaceae: Cells spherical:

Genera, Streptococcus, Micrococcus, Leuconostoc, Sarcina, Azotobacter,
Planococcus.

F. Family, Myxobacteriaceae: Cells more or less rod shaped, non-flagellate,

with slimy membrane, moving slowly forward (Pseudoplasmodia)
which become a cyst, sessile or stalked.
Genera: Polyangium, Chondromyces, Myxococcus.
II. Order, Thiobacteria: Cells with sulfur inclusions, colorless or red or violet
with bacteriopurpurin.

76 GENERAL SYSTEMATIC BACTERIOLOGY

A. Family, Beggiatoaceae: Motile by an undulating membrane, filamen-

tous colonies of colorless, sheathless cells, with sulfur granules.
Genera: Beggialoa, Thiothrix.

B. Family Rhodobacteriaceae: Cell content rose, red, or violet with sulfur

granules.

Genera; Lamprocystis, Thiosarcina, Rhodohacillus, Thiospirillum,

Chromatium.

Meyer (1912, p. 2) recognized as an order the Euhacteria the genera
and generic sections of which may be separated by the following key:

Key to the genera and sections of the Euhacteria according to Meyer (1912)

a. Cells straight rods.

b. Not with polar flagella. Flagella when present-peritrichous.

Genus Bacillus
c. Cells containing bacteriopurpurin.

Section Rhodohacillus
2c. Cells not containing bacteriopurpurin.
d. Flagella unknown.

Section Bacterium
2d. All other species.

Section Eubacillus

2b. With polar flagella Genus Pseudomonas

2a. Cells not straight rods,
b. Cells curved rods.

c. Peritrichous flagella, with spores.

Genus Spirobazillus
2c. Polar flagella, spores unknown,
d. With 5-20 polar flagella.

Genus Spirillum
e. Without bacteriopurpurin.
f. Flagella unknown.

Section Spirosoma
2f. Flagella known.

Section Euspirillum
2e. With bacteriopurpurin.

Section Rhodospirillum
f. Sulphur free.

Subsection a
2f . With sulphur.

Subsection j8
2d. With 1 rarely 2-3 polar flagella.

Genus Microspira
e. With bacteriopurpurin.

Section Rhodospira
2e. Without bacteriopurpurin.

Section Eumicrospira

GENERAL SYSTEMATIC BACTERIOLOGY 77

2b. Cells spherical.

c. Cells in chains Genus Streptococcus

d. Without bacteriopurpin.
e. With flagella.

Section Planostreptococcus
2e. Without flagella.

Section Fixostreptococcus
d. With bacteriopurpurin.

Section Rhodococcus
e. Without sulphur.

Subsection a
2e. With sulphur.

Subsection /3

2c. Cells not in chains Genus Micrococcus

d. Division in two planes.

e. Without bacteriopurpurin.
f. Flagella unkno'5\Ti.

Section Fixococcus
2f. Flagella known.

Section Planotoccus
2e. With bacteriopurpurin.

Section Rhodococcus
f. With sulphur.

Subsection a
2d. Division in three planes.

Genus Sarcina
e. Without bacteriopurpurin.
f. With flagella.

Section Planosarcina
2f. Without flagella.

Section Fixosarcina
2e. With bacteriopurpurin.

Section Rhodosarcina
f. Without sulphur.
Subsection a
2f . With sulphur.

Subsection /3

Lohnis (1913) in his "Vorlesimgen liber landwirtschaftliche Bakte-
riologie" gives the following abbreviated classification of genera.

Lohnis' Classification of Bacteria (1913)

I. Cells as a rule spherical, seldom assuming an elongated form:

a. Single, in pairs, fours, or irregular masses, never in chains.

Micrococcus

b. In shorter or longer chains Streptococcus

c. In packets Sarcina

78 GENERAL SYSTEMATIC BACTERIOLOGY

II. Cells as a rule rod shaped, seldom spherical, or bent:

a. Without endospores Bacterium

b. With endospores Bacillus

III. Cells as a rule slightly to decidedly spirally bent:

a. Comma shaped Vibrio

h. Stiff spirals Spirillum

c. Flexose spirals Spirochaete

Chatton and Perard (1913) introduced the generic names Meta-
bacterium and Oscillospira.

Vuillemin (1913) has given a comprehensive review of bacterial clas-
sification with particular reference to the fact that at the Botanical
Congress that was to have met in 1915 the date of departure and special
rules for bacterial nomenclature were to be considered. He suggested
that the date of departure be fixed as 1915 and that the genera and higher
groups that follow should be adopted as genera conservanda, or "natural
history" genera.

Vuillemin's Classification of Bacteria (1913)

I. Plastids rounded (spherical).

A. Dissociated or grouped without regular order.

1. Polar flagella Planococcus

B. Associated in elementary colonies of determined form.

1. Divisions parallel.

a. Grouped in rosaries Streptococcus

b. Pairs encapsulated, isolated or united into a rosary. Ele-

ments sometimes elongated or pointed.

Klebsiella

2. Division in two planes at right angles.

a. Fission centripetal.

(1) Non-motile Merista

(2) Flagellated Planomerista

b. Fission excentric Neisseria

3. Division in three planes at right angles.

a. Non-motile Sarcinn

h. Flagellated Planosarcina

II. Plastids rod-shaped.

A. Sporiferous elements specialized

1. Oval. Flagella unknown Metabacterium

2. Claviform. Flagella diffuse Clostridium

B. None of the sporiferous elements distinct from the vegetative rods.

1. Flagella diffuse Serratia

2. Flagella polar Bacterium

III. Plastids sinuous.

A. Flagella polar Spirillum

GENERAL SYSTEMATIC BACTERIOLOGY 79

Vuillemin also proposed that the following names be kept as " Form-
ogenera conservanda," but without nomenclatural status, Micrococcus,
Mantegazzaea, Bacillus and Spirosoma.

Gonder (1914) in Prowazek's Handbuch der pathogenen Protozoen
gives the following classification of the spirochetes.

Gonder's Classification of the Spirochetes (1914)

Spirochaeta Ehrb. 1838.

Type species Sp. plicatilis Ehr.
Cristispira Gross 1910.

Type species, Cristispira halhiani.
Spironema Vuillemin 1905.

Type species Spironema recurrentis.
Treponema Schaudinn 1905.

Type species Treponema pallidum.

Buchanan (1915) reviewed the terminology for the Coccaceae pro-
posed by Winslow and Rogers and suggested certain changes that should
be made in names of genera and higher groups the better to recognize
priority.

Buchanan (1917-1918) published a series of articles under the gen-
eral heading of ''Studies in the Nomenclature and Classification of
the Bacteria, " in which were listed the various names of genera and
higher groups which had been recognized in the literature, and a
classification of bacteria into orders, families and genera, with designa-
tion of tj'pe species for the genera. The dichotomous keys to the
groups recognized follow:

Key to the Orders of the Class Schizomycetes (Buchanan) (1917)

A. Plant-like in the principal characters, not protozoan like, cells never slender,
flexuous spirals; cell divisions never longitudinal.
I. Not producing a pseudoplasmodium during the vegetative stage;
without a highly developed, cyst-producing, resting stage,
a. Containing neither granules of free sulphur, nor bacteriopurpurin,
nor requiring the presence of hydrogen sulphid for the best
development.

1. Xot typically producing filaments as a regular growth form,

though chains of cells may be developed. Conidia not
developed, spores when formed are endospores.
Order I. Eubacteriales

2. Typically producing true filaments as a regular growth

form. Conidia may be developed, but never endospores.

(a) Alga-like, typically water forms. Filaments never

showing true branching; false branching maj' be

80 GENERAL SYSTEMATIC BACTERIOLOGY

present. A sheath usually evident, and usually
impregnated with iron.

Order II. Chlamydobacteriales
(b) Mold like, not typically water forms, not with the
sheath impregnated with iron. True branching
often evident.

Order III. Actinomycetales
b. Cells typically containing either granules of free sulphur or
bacteriopurpurin or both, usually growing best in the presence
of hydrogen sulphid.

Order IV. Thiobacteriales
II. Cells united during the vegetative stage into a pseudoplasmodium
which passes over into a highly developed, cyst-producing, resting

stage Order V. Myxobacteriales

B. Protozoan-like in many characters. Cells usually relatively slender flexuous
spirals; multiplication of cells apparently by longitudinal division in some
types, by transverse division in others, or both.

Order VI. Spirochaetales

Key to the families of the Eubacteriales

A. Organisms usually growing more or less readily upon organic media, not

securing growth energy primarily by the oxidation of ammonia or nitrites.
I. Cells typically spherical. .Family I. Coccaceae
II. Cells not spherical, elongate.

a. Cells not spiral Family II. Bacteriaceae

b. Cells spiral, or at least curved.

Family III. Spirillaceae

B. Not growing readily or at all on media containing considerable amounts of

organic material; nitrifying bacteria, securing growth energy primarily by
the oxidation of ammonia or nitrites.
Cells may be either spherical or rod-shaped.

Family IV. Nitrobacteriaceae

Key to tribes of the Coccaceae

1. Not epiphytes, not causing the deposition of iron upon capsules.

A. Commonly parasitic, in some forms saprophytic, usually thriving well

under anaerobic conditions, not commonly producing luxuriant
growths on artificial media, many forms failing to grow except upon
special media. Cells in pairs, chains or irregular masses, never
regular packets. Gram-positive, with exception of a few strict
parasites. Acid usually formed in dextrose and lactose broth.
Pigment white, orange or absent.

Tribe I. Streptococceae

B. Saprophytes, or facultative parasites. Usually grow best under aerobic

conditions, producing abundant to luxuriant growth on artificial
media. Planes of fission often at right angles: Cells aggregated in
groups, packets or zoogloeal masses. Usually Gram-negative.
Pigment as a rule yellow, red or orange.

Tribe II. Micrococceae

GENERAL SYSTEMATIC BACTERIOLOGY 81

II. Epiphytes, usually on leaves and stems of water plants. Iron oxid deposited
upon the capsule Tribe III. Siderocapseae

Key to the genera of the Streptococceae

A. Cells occurring normally in chains.

I. Usually parasitic. Not forming zoogloeal masses in sugar solutions

Genus 1. Streptococcus
II. Saprophytic, occurring in cane sugar solutions in zoogloeal masses.

Genus 2. Leuconostoc

B. Cells not occurring usually or characteristically in chains.

I. Parasitic. Cells in pairs, growth as a rule meagre. No pigment

formed.

a. Gram-positive Genus 3. Diplococcus

b. Gram-negative Genus 4. Neisseria

II. Cells in irregular groups, usuallj^ parasites, growth as a rule good,
pigment usually orange or white.

Genus 5. Staphylococcus

Key to the genera of Micrococceae

A. Cells not in regular packets.

1. Pigment generally yellow Genus 1. Micrococcus

2. Pigment red Genus 2. Rhodococcus

B. Cells in regular packets. Pigment yellow or orange.

Genus 3. Sarcina

Key to the genera of Siderocapseae
One genus only, Siderocapsa.

Key to the tribes of the Bacteriaceae

A. Cells not acid-fast.

I. Typically producing endospores under favorable conditions.

Tribe I. Bacilleae
II. Not producing endospores.. Tribe II. Bacterieae

B. Cells acid-fast, frequently showing some tendency to branching.

Tribe III. Mycobacterieae

Key to the genera of Bacilleae

A. Usually a single endospore formed within each cell.

I. Aerobic usually Gram-positive, as a rule liquefying gelatin, spores
usually not distorting rods when formed.

Genus 1. Bacillus

II. Anaerobic or microaerophilic usually.

a. Spores produced at extreme tip of cells, forming typical drum-

sticks Genus 2. Plectridium

b. Spores not produced at extreme tip of cells, at least not forming

drumsticks. Cells usually somewhat swollen when spores are
formed Genus 3. Clostridium

82 GENERAL SYSTEMATIC BACTERIOLOGY

B. Usually a number of spores develop within a swollen cell.

Genus 4. Metabacierium

Key to the subgenera of Bacillus

A. Spore not barrel-shaped in longitudinal section and not star-shaped in cross

section.

I. Motile by means of peritrichous flagella.

Subgenus 1. Eu-Bacillus
II. Non-motile Subgenus 2. Bacteridium

B. Spore barrel-shaped in longitudinal section, longitudinal striations evident.

Subgenus 3. Astasia

Key to the subtribes of the Bacterieae

A. Cells usually fusiform Subtribe I. Fusiforminae

B. Cells not fusiform.

I. Requiring serum or hemoglobin for development. Obligate parasites.
Gram-negative. Non-motile.

Subtribe II. Hemophilinae
II. Not requiring serum, or at least hemoglobin, for development. Gram-
negative or positive. Motile or non-motile.

a. Obligate aerobes, securing growth energy by oxidation, etc.

Subtribe III. Rhizobiinae

b. Not obligate aerobes, not securing growth energy by oxidation of

carbonaceous compounds.

Subtribe IV. Bacteriinae

Key to the Genera of Fusiforminae

One genus only Fusiformis.

Key to the Genera of Hemophilinae

A. Requiring serum for growth. Cells almost ultra-microscopic. Stain best by

Giemsa. Involution forms characteristic.

Genus 1. Asterococcus

B. Requiring hemoglobin for growth. Stain readily with ordinary aniline dyes.

Involution forms infrequent Genus 2. Hemophilus

Key to the genera of Rhizobiinae

A. Not fixing atmospheric nitrogen; securing growth energy usually by the oxida-

tion of ethyl alcohol to acetic acid.. Genus 1. Mycoderma

B. Capable of fixing appreciable amounts of atmospheric nitrogen. Grow well

on nitrogen-free media.

a. Small motile rods, with abundant involution forms, frequently living in

root nodules of the higher plants (legumes).

Genus 2. Rhizobium

b. Not symbiotic. Cells larger, plump, almost spherical in some cases.

Genus 3. Azotobacter

GENERAL SYSTEMATIC BACTERIOLOGY 83

Key to the genera of Bacteriinae

A. Producing usually a yellowish or greenish or fluorescent pigment, usually

Gram-negative, motile by means of polar flagella, or non-motile.

Genus 1. Pseudomonas

B. When pigmented not greenish or fluorescent, when motile with peritrichoua

flagella.

1. Cells typically pigmented, chromoparous.

a. Producing red or pink pigment.

Genus 2. Serratia

b. Producing a violet pigment.

Genus 3. Chromohacterium

2. Cells not typically definitely pigmented, or at least not red or violet.

a. Cells typically Gram-negative.

(1) Non-motile, showing bipolar staining commonly. Never produce

gas from carbohydrates. Power of acid production low.
Genus 4. PasteureUa

(2) Not showing bipolar staining.

(a) Not producing honej^-like growth on potato, branching

forms uncommon.
X. Gelatinnot liquefied or liquefied very slowly. Motile
or non-motile.

Genus 5. Bacterium
XX. Gelatin liquefied quickly. Motile.
Genus 6. Proteus

(b) Producing a honey-like growth on potato. Branched cells

not uncommon. Genus 7. Pfeifferella

b. Cells typically Gram-positive. All non-motile.

(1) Usually microaerophilic. Not typically growing well on the

surface of laboratory media. Without metachromatic
granules.

(a) Non-pathogenic lactic acid bacilli.

Genus 8. Lactobacillus

(b) Pathogenic, slender, small rods, not lactic acid formers.

Genus 9. Erysipelothrix

(2) Aerobic rods, frequently showing metachromatic granules

or irregular staining. .Genus 10. Corynebacteriuni

Key to the subgenera of Bacterium

A. Organisms which show a maximum of fermentative power, including fermenta-

tion of lactose, rarely pathogenic, some forms slowly liquefy gelatin.

Subgenus 1. Aerobacter (or Eu-Bacterium)

B. Organisms not showing maximum fermentative power, never producing gas in

lactose, frequently pathogenic, never liquefying gelatin.

1. Producing acid and gas from glucose, sometimes other sugars, but none

from lactose Subgenus 2. Salmonella

2. Producing gas from none of the carbohydrates, acid sometimes formed.

Subgenus 3. Eberthella

84 GENERAL SYSTEMATIC BACTERIOLOGY

Key to the Genera of Mycobacterieae
One genus only, Mycobacterium.

Key to Genera of Spirillaceae

A. Cells not larger at center, not tapering.

1. Cells usually short, only a segment of a spiral. One or rarely two or three

polar flagella Genus 1 . Vibrio

2. Cells longer, usually with a tuft of polar flagella.

Genus 2. Spirillum

B. Cells enlarged at center and tapering.

Genus 3. Paraspirillum

Key to the Genera of Nitrobacteriaceae

A. Cells rod shaped.

1. Oxidizing ammonia to nitrous acid. Motile.

Genus 1. Nitrosomonas

2. Oxidizing nitrous acid to nitric acid.

Genus 2. Nitrobacter

B. Cells spherical Genus 3. Nitrosococcus

Key to the Genera of Chlamydobacteriaceae

1. Filaments not usually permanently attached.

a. Filaments straight, or at least not twisted.

Genus 1. Leptothrix

b. Filaments twisted Genus 2. Didymohelix

2. Filaments attached.

a. Filaments unbranched Genus 3. Crenothrix

b. Filaments show pseudodichotomous or false branching.

(1) Swarm cells developed (motile conidia). Usually without a

deposit of iron oxid in the sheath.

Genus 4. Sphaerotilus

(2) Spherical, non-motile conidia. Usually with iron oxide.

Genus 5. Clonothrix

Key to the Genera of Actinomycetaceae

A. No evident aerial threads or conidia formed. Usually parasitic. Often

anaerobic or microaerophilic.

1. Threads usually not branched.

a. Threads disjointing very readily; long mycelial threads uncommon.

Genus 1. Actinobacillus

b. Threads longer, not disjointing into short rods.

Genus 2. Leptotrichia

2. Threads more or less branched, frequently clubbed in tissues.

Genus 3. Actinomyces

B. Aerial threads and conidia evident on culture media.

Genus 4. Nocardia

GENERAL SYSTEMATIC BACTERIOLOGY 85

Key to the Families of Thiobacteriales

A. Cells containing sulphur granules (or in one species possibly oxalate crystals),

but no bacteriopurpurin.

1. Unicellular, motile forms. Not filamentous.

Family I. Achromatiaceae

2. Filamentous forms Family II. Beggiatoaceae

B. Cells containing bacteriopurpurin with or without sulphur granules.

Family III. Rhodobacteriaceae

Key to the Genera of Achromatiaceae

A. Cells spherical or ellipsoidal.

1. Cells ellipsoidal (spherical when newly divided). Cells containing gran-

ules of calcium oxalate (perhaps sulfur).

Genus 1. Achromatium

2. Cells spherical, with sulphur granules in a central vacuole.

Genus 2. Thiophysa

B. Cells longer, very large (42 to 86ju) with peritrichous flagella.

Genus 3. Hillhousia

Key to the Genera of Beggiatoaceae

A. Filament non-motile, with a contrast to base and tip, attached.

Genus 1. Thiothrix

B. Filaments motile (oscillating) not attached, no differentiation into tip and

base.

1. Filaments not in bundles nor surrounded by a gelatinous sheath.

Genus 2. Beggiatoa

2. Filaments in bundles, surrounded by a gelatinous sheath.

Genus 3. Thioploca

Key to the Subfamilies of Rhodobacteriaceae

A. Cells containing sulphur granules.

Subfamily I. Chromatioideae

B. Cells without sulphur granules.. .Subfamily II. Rhodobacterioideae

Key to the Tribes of Chromatioideae

A. Cells united, at least during a part of the life history, into families.

I. Cell division such that masses of cells, not merely plates, are formed.

a. Cell division in three directions of space.

Tribe I. Thiocapseae

b. Cell division first in three, then in two directions of space.

Tribe II. Lamprocysteae
II. Cell division in two planes, forming plates of cells.

Tribe III. Thiopedieae
III. Cell division in one plane. .Tribe IV. Amoebobacterieae

B. Cells free, capable of swarming at any time

Tribe V. Chromatieae

86 GENERAL SYSTEMATIC BACTERIOLOGY

Keij to the Genera of the Thiocapseae

A. Cells capable of swarming.

I. Families small, compact, enclosed singly or several together in a cj'st.

Genus I. Thiocijstis
II. Cells large, 7 to 8/^, loosely bound by gelatin into loose families.

Genus II. Thiosphaera
III. Cells small, united into solid, spherical families.

Genus III. Thiosphaerion

B. Cells not capable of swarming.

I. Spherical cells spread out upon the substratum in flat families, loosely
enveloped in a common gelatin.

Genus IV. Thiocapsa
II. Arranged in regular packets like Sarcina.

Genus V. Thiosarcina

Key to the Genera of Lamprocysteae

One genus only: Lamprocystis.

Key to the Genera of Thiopedieae

A. Cells occurring regularly in fours. . . .Genus I. Lampropedia

B. Cells occurring in a film or membrane, not regularly disposed in tetrads.

Genus II. Thioderma

Key to the Genera of Amoebobacterieae

I. Cells connected by plasma threads, families amoeboid motile.

Genus I. Amoebobacter

II. Cells not as I.

A. Cells arranged in a net, united by their ends.

Genus II. Thiodictyon

B. Cells not arranged in a net.

1. Capable of swarming. Cells loosely aggregated in gelatin.

Genus III. Thiothece

2. Non-motile. Cells closely appressed into a colony.

Genus IV. Thiopoly coccus

Key to the Genera of Chromatieae

A, Cells motile by means of polar flagella. Elongated.

I. Cells not spiral.

a. Cell cylindric Genus I. Chromatium

b. Cells with tendency to spindle shape.

Genus II. Rhabodomonas
II. Cells spiral Genus III. Thiospirillum

B, Cells spherical, or little elongate, non-motile.

I. Cells not encapsulated Genus IV. Rhodocapsa

II. Cells encapsulated in pairs. . .Genus V. Rhodothece

Key to the Genera of Rhodobacterioideae

A. Cells rod shaped, many embedded in the same slimy capsule.

Genus I. Rhodocystis

GENERAL SYSTEMATIC BACTERIOLOGY 87

B. Cells spherical or short rods.

1. In chains, each chain surrounded by a capsule.

Genus II. Rhodonostoc

2. Cells free Genus III. Rhodosphaera

C. Cells free and elongate.

1. Cells not bent.

a. Non-motile Genus IV. Rhodohacterium

b. Motile Genus V. Rhodobacillus

2. Cells bent or curved.

a. Cells short, comma shaped, with single polar flagellum.

Genus VI. Rhodovibrio

b. Cells spiral, with polar flagella

Genus VII. Rhodospirillum

Key to the Genera of Myxobacteriaceae

I. Cells not transformed into coccus-like spores when encysted.

A. Rods forming free cysts in v/hich they remain unmodified. Cysts

various, sessile or borne on a more or less highly developed cystophore.

Genus I. Chondromyces

B. Rods forming large rounded cysts, one or more, free within a gelatinous

matri.x raised above the substratum.

Genus II. Polyangium
II. Rods transformed to form definite, more or less encysted, sessile or stalked
masses of coccus-like spores Genus III. Myxococcus

Key to the Genera of Spirochaetaceae

I. Usually saprophytic, free living in water.

A. Protoplasm spirally wound around an elastic axis filament.

Genus I. Spirochaeta

B. Not as in (A), cross section circular.

Genus II. Saprospira
II. Usually parasitic.

A. Possessing a "crest" or ridge. Parasitic in mussels.

Genus III. Cristispira

B. Without a crest. Parasitic in warm blooded animals.

Genus IV. Treponema

In September, 1917, appeared the Preliminary Report of the Commit-
tee of the Society of American Bacteriologists on Characterization and
Classification of Bacterial Types (Winslow, Broadhurst, Buchanan,
Krumwiede and Smith) . An historical review of systems of classifica-
tion is given, likewise a review of the points found in the International
Botanical Code of principal interests to bacteriologists. Four orders
of bacteria were recognized. The subdivisions of the Eubacieriales
alone were recommended. The classification in outline follows:

88 GENERAL SYSTEMATIC BACTERIOLOGY

Suggested Committee Classification of the Class Schizomycetes (1917)

A. Order. Myxobacteriales.

B. Order. Thiobacteriales.

C. Order. Chlamydobacteriales.

D. Order. Eubacteriales.

I. Family. Nitrobacteriaceae.

1. Genus. Hydrogenomonas.

2. Genus. Methanomonas.

3. Genus. Carboxydomonas.

4. Genus. Mycoderma.

5. Genus. Nitrosomonas.

6. Genus. Nitrobacter.

7. Genus. Azotobacter.

8. Genus. Rhizobium.
II. Family. Mycobacteriaceae.

1. Genus. Actinomyces.

2. Genus. Nocardia.

3. Genus. Mycobacterium.

4. Genus. Corynebacterium.

5. Genus. Fusiformis.

6. Genus. Leptotrichia.

III. Family. Pseudomonadaceae.

1. Genus. Pseudomonas.

IV. Family. Spirillaceae.

1. Genus. Vibrio.

2. Genus. Spirillum.
V. Family. Coccaceae.

a. Tribe. Streptococceae.

1. Genus. Neisseria.

2. Genus. Streptococcus.

3. Genus. Staphylococcus.

4. Genus. AZfeococcus.

b. Tribe. Micrococceae.

1. Genus. Micrococcus.

2. Genus. Sarcina.

3. Genus. Rhodococcus.
VI. Family. Bacteriaceae.

1. Genus. Bacterium.

2. Genus. Erwinia.

3. Genus. Pasteurella.

4. Genus. Hemophilus.
VII. Family. Lactobacillaceae.

1. Genus. Lactobacillus.
VIII. Family. Bacillaceae.

1. Genus. Bacillus.

2. Genus. Clostridium.

GENERAL SYSTEMATIC BACTERIOLOGY 89

E. Organisms intermediate between bacteria and protozoa.

1. Genus. Spirochaeta.

2. Genus. Cristispira.

3. Genus. Saprospira.

4. Genus. Treponema.

An artificial key to the orders and genera was also published as
follows :

1. Artificial Key to the Orders of the Schizomycetes

a. Cells united during the vegetative stage into a pseudoplasmodium.

A. Myxobacteriales
2a. Cells not forming a pseudoplasmodium.

b. Cells free or united in elongated filaments, often with a well-defined
sheath. Conidia frequently formed. Free sulphur, iron or bacterio-
purpurin often present.
c. Cells typically containing granules of sulphur or bacteriopur-

purin or both B. Thiobacteriales

2c. Sulphur and bacteriopurpurin absent; iron often present.

C. Chlamydobacteriales
2b. Cells never in sheathed filaments. Conidia only in the mycelial
Mycobacteriaceae. Flagella often present. Free iron, sulphur, or
bacteriopurpurin never present D. Eubacteriales

2. Artificial Key to the Families of the Eubacteriales

a. Cells spiral with polar flagella IV. Spirillaceae

2a. Not^as above.

b. Cells spherical; rarely, if ever, motile; spores never produced; never
securing growth energy from nitrogen or ammonia.

V. Coccaceae
2b. Not as above.

c. Cells short rod-shaped with a single (rarely two) polar flagellum;
usually forming green or yellow pigment.

III. Pseudomonadaceae
2c. Not wholly as above.

d. Spores formed VIII. Bacillaceae

2d. Spores never formed.

e. Metabolism simple, securing growth energy from car-
bon, hydrogen, or their simple compounds; flagella,

if present, polar I. Nitrobacteriaceae

2e. Metabolism complex, dependent upon more complex
carbohydrate and protein substances; flagella, if
present, peritrichic.

f. Cells clubbed, fusiform, filamentous, branching or
mycelial; those not distinctly so are either acid-
fast or show barred irregular staining.
II. Mycobacteriaceae

90 GENERAL SYSTEMATIC BACTERIOLOGY

2f. Not as above.

g. Gram-positive; non-motile

VII. Lactobacillaceae
2g. Gram-negative; often motile.

VI. Bacteriaceae

3. Artificial Key to the Genera of the Eubacteriales

a. Nitrobacteriaceae.

b. Fixing nitrogen or oxidizing its compounds.
c. Fixing nitrogen.

d. Cells large; in soil 7. Azotobacter

2d. Rods minute; in roots of leguminous plants.

8. Rhizobium
2c. Oxidizing nitrogen compounds.

d. Oxidizing ammonia 5. Nitrosomonas

2d. Oxidizing nitrites 6. Nitrobacter

2b. Not as above.

c. Oxidizing hydrogen 1. Hydrogenomonas

2c. Oxidizing carbon compounds.

d. Oxidizing alcohol; branching forms common.

4. Mycoderma
2d. Not as above, using simpler carbon compounds.

e. Oxidizing CO 3. Carboxydomonas

2e. Oxidizing CH4 2. Methanomonas

2a. Mycobacteriaceae .

h. Slender rods, staining with difficulty and acid-fast.

3. Mycobacterium
2b. Not as above.

c. Mycelium and conidia formed.

d. With aerial hyphae and conidia; usually saphrophytic soil

organisms 2. Nocardia

2d. Hyphae and conidia not aerial; usually parasitic in animals.

1. Actinomyces
2c. Not as above; cells rod-like, usually somewhat curved, clubbed,
fusiform, or even branched, but never mycelial,
d. Thick, long threads, fragmenting into short, thick rods.

6. Leptotrichia
2d. Not as above.

e. Cells usually elongate and fusiform; filaments, if
formed, not branching; staining somewhat irregularly.

5. Fusiformis

2e. Cells slightly curved, clubbed, or in old cultures even
branching ; not filamentous ; showing definitely barred

staining 4. Corynebacterium

3a. Pseudomonadaceae.

Generic characters mainly those of family. . . 1. Pseudomonas
4a. Spirillaceae.

b. Flagellum single (rarely 2 or 3) 1. Vibrio

GENERAL SYSTEMATIC BACTERIOLOGY 91

2b. Flagella tufted (5-20) 2. Spirillum

5a. Coccaceae.

b. Abundant red-pigmented growth on agar.

7. Rhodococcus
2b. Not as above.

c. Gram-negative.

d. Normally in pairs of flattened cells; growth on plain agar
scanty, never bright yellow. 1. Neisseria
2d. Normally in plates, packets, or irregular masses; growth on
plain agar abundant, pigment definitely yellow,
e. Cells in regular packets.. 6. Sarcina
2e. Cells not in regular packets.

5. Micrococcus
2c. Gram-positive (exceptions rare and not easily confused with
above genera).

d. Cells normally in chains, sometimes in pairs (especially in
acid environment) never in large irregular masses. Gela-
tine rarelj^ liquefied. Growth on plain agar usually trans-
lucent, never heavy, never yellow or orange.

2. Streptococcus

2d. Cells normally in groups or masses (occasionally in plates in
Albococcus?) ; chains short and irregular, if present. Gel-
atine often liquefied. Agar growth abundant, white to
orange.

e. Pigment orange (rarely lacking); gelatine often lique-
fied actively 3. Staphylococcus

2e. Whitish to porcelain white; liquefaction less vigorous.

4. Albococcus
6a. Bacteriaceae.

b. Plant pathogens 2. Erwinia

2b. Not as above; saprophytes or in animal habitats (intestines, tissues,
etc.)

c. Usually motile and exhibiting active fermentative powers;
typically parasitic in intestines of man and higher animals;
growing well on ordinary media . . . 1 . Bacterium
2c. Not wholly as above.

d. Growing only in presence of hemoglobin, ascitic fluid or

serum 4. Hemophilus

2d. Growth on media scanty, but less sensitive than the above;
short rods with tendency to bipolar stain.

3. Pasteurella
7a. Lactobacillaceae.

Generic characters mainly those of famih'..l. Lactobacillus
8a. Bacillaceae.

b. Aerobic, usually saprophytic; cells not greatly enlarged (if at all) at

sporulation 1. Bacillus

2b. Anaerobic, often saprophytic; cells frequently enlarged at sporulation.

2. Clostridium

92 GENERAL SYSTEMATIC BACTERIOLOGY

Brief diagnoses were given of all groups recognized, and type species
indicated for the genera.

Castellani and Chalmers (Manual of Tropical Medicine, 3rd edition,
1919), published an unusually detailed classification of the bacteria,
carrying the classification out only to include the most important patho-
genic organisms which have been described. They use as a general
name for the group as a whole, Schizomycetacea. The keys to the vari-
ous groups which they recognize are as follows :

Key to the orders of Schizomycetacea. Castellani and Chalmers (1919)

A. Cells without sulphur or bacteriopurpurin.

Order I. Eubacteriales

B. Cells containing sulphur Order II. Thiobacteriales

C. Motile rods in pseudoplasmodial masses embedded in a gelatinous matrix and

forming highly developed cysts.

Order III. Myxobacteriales

Key to the Families of Eubacteriales

A. Cells, in free condition, usually globular, in division somewhat elliptical.

Family 1. Coccaceae Zopf, 1885, emendavit Migula, 1900

B. Cells, long or short, cylindrical, straight; division one direction.

Family 2. Bacillaceae Fischer, 1894

C. Cells, spirally curved or representing part of a spiral; division in one direction.

Family 3. Spirillaceae Migula, 1900

D. Cells, surrounded by a sheath and arranged in elongated filaments.

Family 4. Chlamydobacteriaceae. Migula, 1900

E. Cells, short or long, cylindrical or filamentous, often clavate, cuneate, or

irregular, with enclosed granules. Filaments without a sheath.

Family 5. Mycobacteriaceae. Chester, 1901

Key to the Tribes of Coccaceae

A. Parasitic on plants and animals, often growing best anaerobically but fre-

quently with difficulty and in small amount, or even not at all, on artificial
media; in pairs or chains, generally but not always staining by Gram, and
often producing acidity in glucose and lactose media, and when pigmented
generally white or orange.
Tribe I. Streptococceae. Trevisan, 1889, emendavit Winslow and Rogers, 1905

B. Facultative parasites or saprophytes growing best under aerobic conditions

and well on artificial media; in cell groups, packets or zoogloea masses and
often Gram-negative, and when pigmented usually yellow or red.
Tribe II. Micrococceae. Trevisan, 1889, emendavit Winslow and Rogers, 1905

Key to the Genera of Streptococceae

A. Gram stain negative Neisseria

B. Gram stain positive:

I. Pigment absent.

a. Cells in zoogloea masses, Ascococcus

GENERAL SYSTEMATIC BACTERIOLOGY 93

b. Not in zoogloea masses :

1. Pairs or chains encapsulated, soluble in bile and salt solu-

tions Diplococcus

2. Chains, not encapsulated, not soluble in bile or salt solutions.

Streptococcus
II. Pigment present :

a. Orange, Aurococcus

h. White, Albococcus

Key to the Genera of the Tribe Micrococceae

A. Pigment red Rhodococcus

B. Pigment yellow:

I. Cells in irregular groups Micrococcus

II. Cells in packets Sarcina

C. Pigment black Nigrococcus

Key to the Tribe of the Family Bacillaceae

Growth in ordinary laboratory media:

A. Entirely or almost entirely absent.

Tribe 1. Nitrobactereae

B. Poor, Gram-negative, grow best on blood media.

Tribe 2. Haemophileae

C. Extremely slow and scanty growth on ordinary and blood media.

Tribe 3. Graciloideae

D. Growth good:

I. Endospores present Tribe 4. Bacilleae

II. Endospores absent:

(a) Fluorescent or chromogenic.

Tribe 5. Bacteridieae

(b) Neither fluorescent nor chromogenic :

1. Obligatory anaerobes Tribe 6. Bacteroideae

2. Aerobes often facultative anaerobes:

(1) Gelatine liquefiers.

Tribe 7. Proteae

(2) Gelatine non-liquefiers :

(i) Without capsules:

(A) With polar staining.

Tribe 8. Pasteurelleae

(B) Without polar staining.

Tribe 9. Ebertheae
(ii) With capsules.

Tribe 10. Encapsulateae

Key to the Tribe Encapsulateae

This tribe contains one genus only Encapsulateae

Key to the Genera of the Tribe Ebertheae

A. Glucose and lactose either not at all or only partially fermented with the
production of acid, but no gas :

94 GENERAL SYSTEMATIC BACTERIOLOGY

I. Milk not clotted:

(.a) Glucose and lactose not fermented.

Genus 1. Alcaligenes Castellan! and Chalmers, 1918

(b) Glucose partially fermented with the production of acid and no

gas; lactose not fermented:

1. Motile. .. .Genus 2. .©feeriAws Castellani and Chalmers, 1918

2. Non-motile.

Genus 3. Shigella Castellani and Chalmers, 1918

(c) Lactose and glucose partially fermented with the production of

acid, but no gas.

Genus 4. Dysenteroides Castellani and Chalmers, 1918
II. Milk clotted:

Glucose partially fermented with the production of acid, but no gas;
lactose not fermented (no gas in any sugar).

Genus 5. Lankoides Castellani and Chalmers, 1918
B. Glucose completely fermented with the production of acid and gas ; lactose not
fermented:

I. Milk not clotted.
Genus 6. Salmonella Lignieres, emendavit Castellani and Chalmers, 1918

II. Milk clotted Genus 7. Balkanella Castellani and Chalmers, 1918

C Glucose completely fermented with the production of acid and gas; lactose

partially fermented with the production of acid and no gas:

I. Milk not clotted. .Genus 8. T'Fesenfcer^us Castellani and Chalmers, 1918

D. Glucose and lactose completely fermented with the production of acid and gas :

I. Milk not clotted. .Genus 9. Enteroides Castellani and Chalmers, 1918

II. Milk clotted. .Genus 10. Escherichia Castellani and Chalmers, 1918

Key to the Subgenera of the Genus Shigella

A. Mannitol fermented Subgenus Flexnerella (Flexner group sensu lata)

I. Maltose fermented Flexner group

II. Maltose not fermented Pseudodysentery group.

B. Mannitol not fermented Subgenus Shigella

Key to the Tribe Pasteurelleae
One genus only: Pasteurella.

Key to the Genera of the Tribe Proteae

A. Rapid gelatine liquefiers; do not ferment lactose; mostly Gram-positive

Proteus

B. Slow gelatine liquefiers; ferment lactose; Gram-negative.

Cloaca

Key to the Tribe Bacteridieae
One genus only: Bacteridium.

Key to the Tribe Graciloideae
One genus only: Graciloides.

GENERAL SYSTEMATIC BACTERIOLOGY 95

Key to the Tribe Bacteroideae
One genus only: Bacteroides.

Key to the Tribe Bacilleae
One genus only: Bacillus.

Key to the Genera of the Family Spirillaceae

A. Non-motile, comma-shaped, or spirally curved filaments, rigid, without

flagella Genus 1. Spirosoma Migula, 1900

B. Motile, short, slightly curved, rigid, comma-like, sometimes in chains, with

one, rarely more, flagella at one end, seldom at both ends.

Genus 2. Vibrio O. F. Miiller, 1773, emendavit Loeffler

C. Motile, long, spirally curved, usually with a bunch of polar flagella composed

of long and short forms.

Genus 3. Spirillum Ehrenberg. 1838 emendavit LoeflHer

Key to the Family Mycobacteriaceae
One genus only: Mycobacterium.

Many of the Hyphomycetes are included under the class Fungi-Imper-
fecti and under the sub-class Hyphales.

Key to the Orders of Hyphornycetes

A. Mycelium composed of fine bacilliform hyphae in which the nuclei are usually

indistinct Order 1. Microsiphonales. Vuillemin, 1912

B. Mycelium not so composed:

1. Reproduction by thallospores.

Order 2. Thallosporales. Vuillemin, 1910

2. Reproduction bj"^ hemispores.

Order 3. Hemisporales. Vuillemin, 1910

3. Reproduction by conidia. .Order 4. Conidiosporales. Vuillemin, 1910

Key to the Families of the Order Microsiphonales

A. Nocardiaceae Castellani and Chalmers, 1918. Synonyms. — Actinoynycetes

Lachner-Sandoval, 1898; Trichomijcetes Petrusky, 1903.
Definition. — Microsiphonales with a mycelium.
Type Genus. — Nocardia Toni and Trevisan, 1889.

B. Mycobacteriaceae Miehe, 1909. Definition. — Microsiphonales without a

mycelium.
Genus 1. — Mycobacterium Lehmann and Neumann, with the diphtheria

bacillus as a type.
Genus 2. — Corynebacterium Lehmann and Neumann, with the tubercle bacillus

as a type.

Key to the Family Nocardiaceae

A. Grows aerobically, easy of cultivation, and producing arthrospores (Fig. 549).

Genus 1. Nocardia Toni and Trevisan, 1889

96 GENERAL SYSTEMATIC BACTERIOLOGY

B. Grows best anaerobically, but can often grow aerobically; diflBcult of culture,
and not producing arthrospores Genus 2. Cohnistreptothrix Pinoy, 1911

Mrs. Enlows (1920) prepared a most helpful bulletin in which was
listed the various names which have been proposed by various writers
for bacterial genera. She has in most cases indicated the type species.

Castellani and Chalmers (1920) proposed a classification of the family
Bacillaceae Fischer 1894 into some 10 tribes differentiated by the fol-
lowing key :

Key to Tribes of Bacillaceae

A. No development in ordinary media Nitrohactereae

B. Growth poor in ordinary media, better on media containing blood. Gram-

negative Hemophileae

C. Very poor and slow growth on ordinary media, also on blood media.

Graciloideae

D. Good development on ordinary media.

I. Endospores present Bacilleae

II. Endospores absent.

a. Fluorescent or chromogenic Bacteroideae

b. Neither fluorescent nor chromogenic.

1. Obligate anaerobes Bacteroideae

2. Aerobic, often facultative anaerobic.

(a) Liquefying gelatin Proteae

(b) Not liquefying gelatin.

(1) Without capsules.

X. Bipolar staining. '

Pasteurelleae
2x. No bipolar staining.

Ebertheae

(2) With capsule Encapsulateae

It will be noted that there is an evident misprint, as both tribes
5 and 6 are termed Bacteroideae.

Three of the tribes are discussed in detail. The generic keys are
given below.

Tribe Encapsulateae
The type and only genus is Encapsulatus Castellani and Chalmers.

Tribe Ebertheae
A. Either do not ferment glucose and lactose at all, or only partially, with pro-
duction of acid without gas .
I. Milk not coagulated.

a. Ferments neither glucose nor lactose.

Alcaligenes. Castellani and Chalmers, 1918

GENERAL SYSTEMATIC BACTERIOLOGY 97

b. Ferments glucose partially, with production of acid but no gas,

does not ferment lactose.

1. Motile Eberthus. Castellani and Chalmers, 1918

2. Non-motile Shigella. Castellani and Chalmers, 1918

c. Ferment glucose and lactose partially with production of acid,

but without gas. .Dysenteroides. Castellani and Chalmers, 1918
II. Milk coagulated. Partial fermentation of glucose with production of
acid but no gas: does not ferment lactose (no gas from any sugar)

Lankoides. Castellani and Chalmers, 1918

B. Ferment glucose completely with production of acid and gas, but do not fer-

ment lactose.

I. Do not coagulate milk.

Salmonella. Lignieres emendav. Castellani and Chalmers
II. Coagulates milk Balkanella. Castellani and Chalmers

C. Ferment glucose completely with production of acid and gas; lactose partially

fermented with acid and no gas, does not coagulate milk.

Wesenbergus. Castellani and Chalmers, 1918

In May 1920 the final report of the Committee (Winslow et al., was
pubUshed. The principal changes from the suggested grouping of
1917 were as follows:

The group recognized in 1917 as the family Mycobacteriaceae has now been ele-
vated to the rank of an order Actinomycetales, and divided into two families,
Actinomycetaceae and Mycobacteriaceae. To the former family we have added the
genera Actinobacillus and Erysipelothrix, and we have omitted Nocardia, which
Breed (1919) has recently shown should be combined for the present with Actino-
myces. To the second family we have added the genus Pfeifferella.

The Nitrobacteriaceae have been divided into two tribes, the Nitrobactereae and
Azotobactereae, and the definition of the family has been modified to permit the
inclusion of Rhizobium which recent investigations have shown to possess peri-
trichous flagella, but whose general characteristics ally it clearly with Azotobacter.
The name Acetobacter has been substituted for Mycoderma to characterize the
vinegar organisms.

Among the Coccaceae a new tribe was created for the genus Neisseria. The
genus Albococcus is united with Staphylococcus and the new genera Diplococcus
and Leuconostoc are added.

The Bacteriaceae are divided into seven tribes: Chromobactereae, Erwineae,
Bactereae, Lactobacilleae, Pasteur ell eae, Hemophileae, and Zopfeae, and the new
genera Erythrobacillus, Chromobacterium, Zopfius, and Proteus are added. The
Lactobacillaceae, originally recognized as a distinct family, are thus classed as a
tribe of the Bacteriaceae.

Artificial Key to the Families and Genera of the Actinomycetales and
Eubacteriales. Winslow et al. (1920)

A. Typically filamentous forms. Actinomycetaceae.

B. Mycelium and conidia formed Actinomyces

98 GENERAL SYSTEMATIC BACTERIOLOGY

BB. No true mycelium.

C. Cells show branching.

D. Gram-negative Actinobacillus

DD. Gram-positive Erysipelothrix

CO. Cells never branch. Gram-positive threads later fragmenting

into rods Leptotrichia

AA. Typically unicellular forms (although chains of cells may occur).
B. Spherical cells. Coccaceae.

C. Parasitic forms. Cells in pairs, chains or irregular groups, never
in packets. Generally active fermenters.
D. Cells in flattened coffee-bean-like pairs. Gram-negative.

Neisseria.
DD. Cells not as above. Gram-positive.

E. Cells in lanceolate pairs or chains.
Growth on media not abundant.
F. Cells in lanceolate pairs. Inulin generally fer-
mented Diplococcus

FF. Cells in chains. Inulin generally not fermented.
Streptococcus
EE. Cells in irregular groups. Growth on media fairly
vigorous.
White or orange Tpigment . Staphylococcus
CC. Saprophytic forms. Chains occurring in zoogleal masses in sugar

solutions Leuconostoc

CCC. Saprophjrtic forms. Cells in irregular groups or packets, not in
chains. Fermentative powers low.

D. Packets formed Sarcina

DD. No packets.

E. Yellow pigment Micrococcus

EE. Red pigment Rhodococcus

BB. Rods.

C. Curved rods. Spirillaceae.

D. Short comma-like rods. One to three short flagella.

Vibrio
DD. Long spirals, five to twenty flagella.

Spirillum
CC. Straight rods.

D. No endospores.

E. Rods of irregular shape or showing branched or filamen-
tous involution forms.

F. Animal parasites. Cells of irregular shape.
Staining unevenly.

G. Acid fast Mycobacterium

GG. Not acid fast.

H. Cells elongate, fusiform.
Fusiformis
HH. Cells not fusiform, sometimes branching.

GENERAL SYSTEMATIC BACTERIOLOGY 99

I. Gram -positive. Slender, sometimes
clubbed rods.

Corijnebacterium
II. Gram-negative. Rods sometimes
form threads. Characteristic
honey like growth on potato.
Pfeifferella
FF. Not animal parasites. Cells staining unevenly
and with branched or filamentous forms at cer-
tain stages. Never acid fast.
G. Metabolism simple, growth processes in-
volving oxidation of alcohol or fixation of
atmospheric nitrogen (latter in symbiosis
with green plants).

H. Cells minute, sjrmbiotes in roots of
leguminous plants.
Rhizobium
HH. Oxidizing alcohol, branching forms com-
mon Acetobacter

GG. Not as above. Proteus-like colonies.

H. Not attacking carbohydrates. Gram +
Zopfius
HH. Fermenting glucose and sucrose. Gram —
Proteus
EE. Regularly formed rods.

F. Metabolism simple, growth processes involving
oxidation of carbon, hydrogen or their simple
compounds or the fixation of atmospheric nitro-
gen. Nitrobacteriaceae.

G. Fixing nitrogen or oxidizing its compounds.
H. Fixing nitrogen.
Cells large; in soil.

Azotobacter
HH. Oxidizing nitrogen compounds.
I. Oxidizing ammonia.
Nitrosomonas
II. Oxidizing nitrites
Nitrobacter
GG. Not as above.

H. Oxidizing hydrogen.

Hydrogenomonas
HH. Not as above, using simpler carbon com-
pounds.
I. Oxidizing CO.

Carboxydomonas
II. Oxidizing CH4.

Methanomonas

100 GENERAL SYSTEMATIC BACTERIOLOGY

FF. Not as above.

G. Flagella usually present, polar. Pseudo-
monadaceae. . .Pseudomonas
GG. Flagella when present perithrichic. Bacteria-
ceae.

H. Parasitic forms showing bipolar staining
Pasieurella
HH. Not as above.

I. Strict parasites growing only in
presence of hemoglobin or ascitic
Quid. Hemophilus
II. Not as above.

J. Water forms producing red or
violet pigment.
K. Pigment red.
Erythrobacillus
KK, Pigment violet.
Chromobacterium
JJ. Not as above.

K. Plant pathogens.
Enuinia
KK. Not as above.

L. Gram positive, form-
ing large amount of
acid from carbohy-
drates and some-
times CO2 but no Ht
Lactobacillus
LL. Gram negative, form-
ing H2 as well as
CO2 if gas is pro-
duced.
Bacterium
DD. Endospores present, Bacillaceae

E. Aerobes Bacillus

EE. Anaerobes Clostridium

Orla-Jensen (1921) suggested certain revisions in his classification,
introducing the new generic names Fluormonas, Photomonas, Pro-
pionococcus, Microhacterium, Colibacterium, Aerogenesbacterium, Buty-
riclostridium and Putriclostridium.

Hilda Hempl Heller (1921, p. 549) suggested that Bacteria be recog-
nized as a phylum, and the principal groups be differentiated as
follows :

GENERAL SYSTEMATIC BACTERIOLOGY 101

Key to the Orders of the Bacteria. Heller (1921)

Simple, one-celled plants that multiply typically by binary fission and occa-
sionally by budding. They show no form of sexual multiplication. They rarely
contain cellulose and do not contain chlorophyll or phycocyanin.

Phylum 1. Bacteria

A, Bacteria which do not form a complex fruiting body.

Class I. Eubacterieae
Eubacterieae whose cells are never in sheathed filaments. Conidia not observed.
Free iron sulphur or bacteriopurpurin never present. Multiplication always

occurs by transverse fission Order I. Eubacteriales

Sulphur bacteria Order II. Thiobacteriales

Iron and manganese bacteria. . .Order III. Chlamydobacteriales

B. Bacteria which join to form a complex fruiting body.

Class II. Myxobacterieae

She also added to the "Committee's" Hst of famiHes of the Eubacte-
riales, the Clostridiaceae: with two subfamihes, the Clostridioideae
and Putrificoideae. A key to the genera of the Clostridioideae was
later (1922, p. 5) pubHshed as follows:

Key to the Genera of the Subfamily Clostridioideae. Heller (1922)

A. Do not produce H2S demonstrable by lead-acetate-paper test were grown
in blood-broth
B. Do not liquefy gelatin.

C. Very large rods that form oval spores and store up starch in car-
bohydrate media Genus 1. Clostridium Prazmowski

emend. Heller. Type species bu-
tyricum as described by Winogradsky
(1895).
CC. Rods with spherical spores.

D. Do not grow on media containing much protein.

Genus. 2. Omelianskillus . nov. gen.
Type species hydrogenicus as described
by Omeliansky (1895 and 1904b).
DD. Grow on ordinary anaerobe media.

E. Sides of the bacilli parallel, spores strictly terminal.

Genus 3. Macintoshillus nov. gen.
Type species tetanomorphus (pseu-
dotetanus bacillus, Mcintosh (p. 32),
Bacillus tetanomorphus Committee (p.
41), as described by the Committee.
EE. Spores not always strictly terminal, sides of bacilli
may not be parallel.

Genus 4. Douglasillus nov. gen. Type
species sphenoides (Bacillus sphen-
oides Douglas, Fleming and Cole-
brook), as described by the Com-
mittee (p. 43).

102 GENERAL SYSTEMATIC BACTERIOLOGY

CCC. Slender rods with oval endospores, usually Gram-negative.

D. Clot milk and attack various sugars, produce much acid.
Genus 5. Henrillus nov. gen. Type
species terlius (Bacillus tertius Henry)
as described by Henry.
DD. Do not clot milk, attack few or no sugars, produce little acid.
Genus 6. Flemingillus nov. gen. Type
species cochlearius [Bacillus coch-
learius Douglas, Fleming and Cole-
brook) as described by the Committee
(p. 40).
CCCC. Gram-positive rods which are not markedly slender and which
produce oval spores.
D. Clot milk, saccharolytic.

E. Sporulate meagerly, attack a few sugars; occasionally
moderately pathogenic tissue invaders.

Genus 7. Vallorillus, nov. gen. Type
species fallax {Bacillus fallax Wein-
berg and Seguin) as described by the
Committee (p. 27).
EE. Sporulate readily, attack several sugars; not known to
be pathogenic.

Genus 8. Multifermentans nov. gen.
Type species tenalhus [Bacillus multi-
fermentans tenalhus Stoddard) as de-
scribed by Stoddard (1919b).
DD. Do not clot milk. Large Gram-positive rods with long
ellipsoid spores.. .Genus 9. Hiblerillus nov. gen. Type
species sextus (bacillus VI of von
Hibler) as described by von Hibler
(1908). (Resume by Weinberg and
Seguin (p. 202).
BB. Liquefy gelatin.

C. Produce stormy fermentation of milk and sporulate on alkaline

media only Genus 10. Welchillus nov. gen. Type

species aerogenes [Bacillus aerogenes
capsulatus Welch and Nuttall), type 1
as defined by Simonds (1915 a and b).
CC. Do not produce stormy fermentation of milk.

D. Do not sporulate.. .Genus 11. Stoddardillus nov. gen.
Type species egens [Bacillus egens
Stoddard) as described by Stoddard
(1919a).
DD. Sporulate readily.

E. Gram-positive, form woolly colonies in deep agar.
Typically highly pathogenic tissue invaders of many
species of animals.

Genus 12. Rivoltillus nov. gen. Type
species vibrion (the vibrion septique of
Pasteur) as defined in a future paper.

GENERAL SYSTEMATIC BACTERIOLOGY 103

EE. Gram-negative, may contain Gram-positive granules.
Form smooth lenticular or modified lenticular colonies
in deep agar. Typically pathogenic for cattle, sheep,
and guinea-pigs.

Genus 13. Arloingillus nov. gen. Type

species Chauvoei (Bacterium Chauvoei

Arloing, Cornevin and Thomas) as

described in a future paper.

AA. Produce HjS demonstrable by a lead-acetate-paper test when grown in blood

broth.

B. Produce a large amount of gas from carbohydrates. Heavy Gram-
positive rods with little or no tendencj^ to sporulation.

Genus 14. Meyerillus nov. gen. Tjrpe
species sadowa nov. sp. to be described
in a future paper.
BB. Produce less gas from carbohydrates. Heavy Gram-positive or Gram-
negative rods that form oval spores that are usually subterminal

Genus 15. Novillus nov. gen. Type
species maligni (Bacillus oedematis
maligni II. Novy) as described by
Novy.

A committee of the Society of American Bacteriologists (Bergey,
Breed, Hammer, Harrison and Huntoon) have recently (1923) prepared
a Manual of Determinative Bacteriology. In general, the classification
suggested by Winslow et al. has been followed. In some groups genera
have been added, and several new families created. In the treatment of
the Bacteriaceae they have followed Castellani and Chalmers and in
orders other than Euhacteriales they have followed Buchanan. The
keys for differentiation of orders, families and genera follow.

The Classification of Bacteria according to Bergey et al. (1923)
Key to the Orders of the Class Schizomycetes

1. Simple and undifferentiated forms, the true bacteria.

Euhacteriales

2. Specialized or differentiated forms.

a. Plant like.

b. Mold like Actinomycetales

bb. Not mold like.

c. Sheathed Chlamydobacteriales

cc. Not sheathed.

d. Sulphur bacteria Thiobacteriales

dd. Slime-mold like Myxomycetales*

aa. Protozoan like Spirochaetales

* A misprint for Myxobacteriales.

104 GENERAL SYSTEMATIC BACTERIOLOGY

Key to Families of the Order Eubacteriales

1. Organisms obligate aerobes, using oxygen for direct oxidation of carbon,

hydrogen, or nitrogen or compounds of these. Cells usually rod-shaped,
occasionally spherical Nitrobacteriaceae

2. Not securing growth energy as under I.

a. Cells spherical Coccaceae

aa. Cells not spherical.

b. Cells spiral Spirillaceae

bb. Cells straight rods.

c. Not producing endospores. Cells motile or non-motile.

Bacteriaceae
cc. Producing endospores Bacillaceae

Key to the Tribes and Genera of the Family Nitrobacteriaceae

1. Organisms oxidize simple compounds of carbon and nitrogen.

Nitrobactereae

a. Cells capable of securing growth energy by the oxidation of hydrogen to

form water Hydrogenomonas

b. Cells oxidize methane to form CO2 and water.

Meihanomonas

c. Cells oxidize CO to form CO2 Carboxydomonas

d. Cells oxidize ammonia to form nitrites Nitrosomonas

e. Cells oxidize nitrites to nitrates Nitrobacter

f. Cells oxidize alcohol to form acetic acid Acetobacter

g. Cells oxidize compounds of sulphur Thiobacillus

2. Organisms capable of fixing free nitrogen of the air.

Azotobactereae

a. Cells capable of fixing free atmospheric nitrogen when growing in solu-

tions of carbohydrates Azotobacter

b. Cells capable of fixing free nitrogen when growing symbiotically on the

roots of Leguminosae Rhizobium

Key to the Tribes of the Family Coccaceae

I. Strict parasites, failing to grow or growing very poorly on usual artificial
media. Cells normally in pairs, occasionally in tetrads.

Neissereae
II. Parasites (except Leuconosioc) growing best in media containing serum.

Occur in pairs or chains Streptococceae

III. Facultative parasites or saprophytes. Cell aggregates of groups, packets
or zoogleal masses. Growth abundant Micrococceae

Key to the Genera of the Tribe Neissereae
One genus only: Neisseria.

GENERAL SYSTEMATIC BACTERIOLOGY 105

Key to the Genera of Tribe Streptococceae

1. Parasites growing poorly, or not at all, on artificial media.
Cells usually in pairs Diplococcus

2. Saprophytes, usually growing in cane sugar solutions. Cells in pairs or chains.

Leuconostoc

3. Chiefly parasites. Normally forming short or long chains, sometimes pairs,

but never packets Streptococcus

4. Parasites. Cells in groups or short chains, rarely in packets.

Staphylococcus

Key to Genera of Tribe Micrococceae

1. Facultative parasites or saprophytes. Cells in plates or irregular masses

(never in long chains or in packets) Micrococcus

2. Cell division occurs in three planes forming packets.

Sarcina

3. Saprophytes. Cells in groups or packets. Form red pigment on agar.

Rhodococcus

Key to the Genera of Family Spirillaceae

1. Cells short, bent rods, rigid, single or united into spirals.

Vibrio

2. Cells rigid, of various thickness and length and pitch of the spiral, forming

either long curves or portions of a turn Spirillum

Key to the Tribes of Family Bacteriaceae

1. Produce pigment on solid media. The pigment may be red, yellow, violet,

green or blue Chromobactereae

2. Without pigment formation on agar or gelatin . Achromobactereae

3. Cellulose digesting organisms occurring in soil. Cellulomonadeae

4. Plant pathogens, growth usually whitish Erwineae

5. Gram-positive rods, growing freely on artificial media. Do not attack

carbohydrates Zopfeae

6. Gram-negative rods growing freely on artificial media. Generally act on

carbohydrates with formation of acid and gas.

a. Without capsules Bactereae

7. b. Encapsulated Encapsulateae

8. Rods often long and slender. Gram-positive. Non-motile. Usually pro-

duce lactic acid from carbohydrates Lactobacilleae

9. Anaerobic, non-spore-forming rods Bacteroideae

10. Gram-negative rods, showing bipolar staining. Parasitic forms.

Pasteurelleae

11. Minute parasitic forms growing only (or best) in the presence of hemoglobin,

ascitic fluid or other body fluids Hemophileae

Key to the Genera of Tribe Chromobactereae

1. Small, aerobic rods, producing a red or pink pigment on agar or gelatin.

Serratia

106 GENERAL SYSTEMATIC BACTERIOLOGY

2. Small, aerobic rods, producing a yellow pigment on gelatin or agar.

Flavobacterium

3. Small, aerobic rods, producing a violet pigment on solid media.

Chromobacterium

4. Small, aerobic rods, producing a green or blue-green pigment.

Pseudomonas

Key to the Genera of the Tribe Achromobactereae
One genus only: Achromobacter.

Key to the Genera of the Tribe Cellulomonadeae
One genus only: Cellulomonas.

Key to Genera of Tribe Erwiniae

1. Motile rods.

a. Flagella peritrichous Erwinia

2. Rods motile or non-motile. Motile forms possess polar flagella.

Phytomonas

Key to the Genera of the Tribe Zopfeae
One genus only: Zopfius.

Key to the Genera of Tribe Bactereae

A. Ferment dextrose with production of acid or acid and gas.

1. Gas formed from dextrose.

a. Gas formed from lactose.

b. Acetyl-methyl-carbinol not formed from dextrose.

Escherichia
bb. Acetyl-methyl-carbinol formed. .Aerobacter
aa. Gas not formed from lactose.

b. Gas formed from sucrose Proteus

bb. Gas not formed from sucrose. . .Salmonella

2. Gas not formed from dextrose.

a. Acid formed from dextrose Eberthella

AA. Do not form acid or gas from any of the carbohydrates.

Alcaligenes

Key to the Genera of the Tribe Encapsulateae
One genus only: Encapsulatus,

Key to the Genera of the Tribe Lactobacilleae
One genus only: Lactobacillus.

Key to the Genera of the Tribe Bacteroideae
One genus only : Bacteroides.

Key to the Genera of the Tribe Pasteurelleae
One genus only: Pasteurella.

GENERAL SYSTEMATIC BACTERIOLOGY 107

Key to Genera of Tribe Hemophileae

1. Aerobic species Hemophilus

2. Anaerobic species Dialister

Key to the Genera of Family Bacillaceae

A. Aerobic forms, mostly saprophites Bacillus

B. Anaerobic forms. Often parasitic Clostridium

Key to the Families of the Order Actinomycetales

A. Filamentous forms, often branched, sometimes forming mycelia. Conidia

sometimes present. Some species parasitic. .Actinomycetaceae

B. Parasitic forms. Rod-shaped, rarely filamentous, and with only slight and.

occasional branching. No conidia Mycobacteriaceae

Key to the Genera of Family Actinomycetaceae

A. Parasitic forms.

a. Aerobic Actinobacillus

h. Anaerobic or facultative Leptotrichia

B. A few parasitic forms; mostly soil forms.

a. Filamentous, often branched, sometimes forming mycelia.

Actinomyces

b. Rods forming long filaments which rarelj' show branching.

Erysipelothrix

Key to the Genera of Family Mycobacteriaceae

A. Slender rods; acid fast Mycobacterium

B. Slender, often slightl}' curved rods; not acid-fast.

Corynebacterium

C. Obligate parasites. Cells frequently fusiform.

Fusiformis

D. Slender, Gram-negative rods Pfeifferella

Key to the Families of the Order Chlamydobacteriales
One family only: Chlamydobacteriaoeae.

Key to the Genera of the Family Chlamydobacteriaceae

1. Filaments usually not permanently attached.

a. Filaments straight or at least not t-wisted. . Leptothrix
h. Filaments twisted Didymohelix

2. Filaments attached.

a. Filaments unbranched Crenothrix

b. Filaments show pseudodichotomous branching.

1. Swarm cells developed (motile conidia). Usually without a deposit

of iron in the sheath Sphaerotilus

2. Spherical, non-motile conidia. Usually with iron oxide.

Clonothrix

108 GENERAL SYSTEMATIC BACTERIOLOGY

Key to the Families of the Thiobacteriales

The keys to the subgroups and genera of this order are the same in general as
those of Buchanan (1917-18) q.v.

Key to the Families of the Order Myxobacteriales

One family only: Myxobacteriaceae.

Key to the Genera of Family Myxobacteriaceae

I. Rods transformed into coccus-like spores when encysted, sessile or stalked

masses of coccus-like spores Myxococcus

II. Cells not transformed into coccus-like spores when encysted.

A. Rods forming large, rounded cysts, one or more within a gelatinous

matrix raised above the substratum. . . . Polyangium

B. Rods forming cysts in which they remain unmodified. Cysts various,

sessile or borne on a more or less highly developed cystophore.

Chondromyces

Key to the Families of the Order Spirochaetales

One family only: Spirochaetaceae.

Key to the Genera of Family Spirochaetaceae

A. Usually saprophytic, free-living in water.

1, Protoplasm spirally wound around an elastic axis filament.

Spirochaeta

2. Cross section circular Saprospira

B. Usually parasitic.

1. Possessing a "crest" or ridge. Parasitic in mussels.

Cristispira

2. Without crest. Parasitic in warm blooded animals and in man.

Spironema
Treponema

3. Short, sharply twisted spirals. Parasitic in rodents and in man.

Leptospira

CHAPTER II

Codes of Nomenclature and Their Application in
Bacteriology

If it be taken as a guiding principle that for each kind of organism
there should be one valid name, and that there should be some criterion
as to the correctness or validity of any name, it is evident that there
must be developed and recognized some code of rules or laws. Such
so-called "Codes of Nomenclature" have been developed both in Botany
and in Zoology by International Congresses called among other
things for this purpose. Inasmuch as the bacteria are plants, or
at least most closely allied to the plant kingdom, it would be
most natural to follow the botanical code. However, an element
of confusion in practice is introduced because bacteriologists
have shown a tendency in recent years to term themselves
microbiologists and their subject microbiology to make it evident
that their studies are not confined to the bacteria, or even to the
plant kingdom. This has been fostered by the discovery of many
diseases of man and animals caused by protozoa. In many cases these
can be best studied by the methods which have been developed in the
bacteriological laboratory. It has proved somewhat confusing to use
the botanical code for the plant forms and the zoological code for the
protozoa.

A careful study of the botanical and zoological codes will show them
to be very similar in most essential characteristics. The botanical
code is less rigid, and probably has something more of ambiguity in
some of its statements than does the zoological. Logically it would
seem that we should follow the botanical code with the bacteria and the
zoological code with the protozoa.

The questions at once arise :

Are these codes really applicable to the nomenclature of micro-
organisms? Have they not been planned with higher groups of plants
and animals in mind?

A careful study of the provisions of either code will show that there
is no inherent difficulty in application to the lower forms of life. In
the botanical code there are, perhaps, one or two rules which the bacte-
riologists might be reluctant to accept, particularly the rule that all

109

110 GENERAL SYSTEMATIC BACTERIOLOGY

new species of plants (in our case, bacteria) to be recognized as valid,
must be published with a Latin diagnosis. From the standpoint at
least of the bacteriologist it would be greatly improved by the introduc-
tion of the type concept. Furthermore, in both botanical and zoologi-
cal codes there is a rule that no two genera (or other groups) can exist
with the same name, and that duplicate genera in plant and animal
kingdoms should be avoided as far as possible, but that such duplicates
are not invalid. In other words, two plants can not have the same
name, nor can two animals, but a plant and an animal may be named
alike. It would appear that for the sake of the microbiologist there
might be appended to each code the rule that in those groups whose
position in plant or animal kingdom is in doubt there should exist no
duplicate names. There is no reasonable question that the zoological
code is the clearer.

In a final determination or formulation of the practice which will
best serve the bacteriologist, and particularly in the formulation of a
statement to govern practice in the present series, it will be necessary- to
discuss :

a. The principles suggested by bacteriologists before the latest
revision of the botanical code, particularly the Rules of Nomenclature
suggested by Lehmann and Neumann.

b. The Botanical Code of Vienna as modified at Brussels.

c. The Zoological Code.

d. The suggestions and recommendations of the Society of American
Bacteriologists.

e. Suggested revision of the botanical code formulated by a com-
mittee of the Botanical Society of America.

A. THE RULES OF BACTERIAL NOMENCLATURE ACCORDING TO

LEHMANN AND NEUMANN

Apparently the first bacteriologists to give very serious consideration
to rules of nomenclature governing the naming of bacteria and to the
formulation of such rules were Lehmann and Neumann. In general it
may be said that these rules conformed measurably weU to the principles
of the botanical code. They undoubtedly constituted a very real
advance over any previous statement. They are of sufficient import-
ance to warrant their inclusion. The translation of the rules is given in
smaller type. The comments are those of the author.

1. Every plant and, therefore, every Schizomycete belongs to a species, every
species to a genus, and every genus to a family.

GENERAL SYSTEMATIC BACTERIOLOGY 111

2. Following the precedent of Linnaeus, every plant or animal, therefore,
every microorganism must have two Latin names : the first designating the genus
to which the organism in question belongs, this name being a substantive; the
second indicating the species, which name is an adjective (not two) or the genitive
of a substantive, or rarely a substantive in the nominative case.

Comment. The first two rules are basic, and generally accepted in
all codes.

3. Genera must only be founded upon important morphologic character-
istics; so called "biologic genera," such as Photobacterium for all light-emitting
bacteria, Pyohacterium for rods causing suppuration, etc., are only calculated
to produce confusion.

Comment. Modern tendency in bacteriology is to disregard this rule
in part. Many valid genera are recognized at present in which physio-
logic as well as morphologic characters are used for purposes of diagnosis
and differentiation.

4. As a designation for species many authors have used, instead of one adjec-
tive or substantive, a plurality of adjectives, evidently with the object of furnish-
ing a description through the name : Bacillus rosettaceus metalloides, Staphylococ-
cus pyogenes aureus, Bacillus pyogenes foeddus, Bacillus mesentericus panis
viscosi I and II. This effort can be understood, but it has been abandoned as
entirely impracticable by all descriptive naturalists since Linnaeus. The name
of the species should indicate this unequivocally; the characterization belongs
to the description. It does no harm if two or more organisms possess names
which mean the same, if they do not sound alike. In addition to a Micrococcus
albus, a Micro, niveus, Micro, albissimus, Micro, candicans, and a Micro, purus,
may all be quite valid; we must look to the description to determine the exact
differences which exist among these white cocci.

5. Names which have been formed improperly, i.e., contrary to the binomial
rule, may be replaced. We have done this with the greatest consideration for the
existing name whenever possible. We have not changed names like Bacillus
acidi lactici, because acidum lacticum represents a single idea, and names like
Sempervivum Reginae Amaliae, Pedicularis Friderici Augusti, Trigonella Foenum
Graecum, Pedicularis Sceptrum carolinum have remained, although certainly not
convenient, still uncontested.

6. If names are properly formed in the binomial manner and correctly pub-
lished, then they must not be changed by the author himself, much less by others,
even if subsequently another appears better. Furthermore, the fact that a name
is philologically incorrect or not beautiful, is no adequate reason for change.
Even, for example, if it were literally more correct to call the genus we have
named "Mycobacterium" by the new name " Tuberculomyces," such a proposition
is absolutely unallowable. Renaming is required only when the name given was
employed earlier with another signification. Thus, Cohn founded upon a cer-
tain organism the new genus Streptothrix, without knowing that Corda, about
thirty years previously had conferred this name upon a fungus totally different

112 GENERAL SYSTEMATIC BACTERIOLOGY

from the one which he described. His new species, therefore, must receive a new
genus name which he who first observed Cohn's oversight is justified in
establishing.

7. It may happen that an author differs from his predecessor as to the bound-
aries of certain genera, and he, therefore, transfers a species from one genus into
another, either one which previously existed or which is newly formed by himself.
This is permissible; nevertheless the designation of the species must not be
changed. So we had the right when we broke up the very large genus Bacillus,
following the suggestion of Hiippe, into the two genera Bacillus and Bacterium,
to rename a number of species (for example. Bacillus pyocyaneus renamed Bac-
terium pyocaneum), but we did not have the right, however much we disliked the
species name pyocyaneum, to rename the organism Bacterium coeruleo-viride or
Bacterium gessardi or anything else.

8. The author who names the genus places his name after the name given.
We speak of Bacillus Cohn, and mean the genus Bacillus as Cohn established it;
of Vibrio Ehrenberg emend. Loeffler, and mean the genus Vibrio as established
by Ehrenberg and afterward more accurately described by Loeffler.

9. Whoever discovers a new species or names one not previously named
gives it a genus and a species name, and places his own name after the latter.
Fliigge, who first named a large number of bacteria, gave, for example, the name
Bacillus pyocyaneus Fliigge, to the long known cause of bluish green suppuration.

10. When one places a species in a new genus he puts his own name after the
new name, thus. Bacterium pyocyaneum Lehmann and Neumann, but it is always
to be recommended that he add in parentheses, the name of the author who first
named the species. Therefore we always write, where it does not become too
cumbersome (in titles, etc.). Bacterium pyocyaneum (Fliigge) Lehmann and
Neumann.

While we believe that all names which express the systematic position of the
organisms shall conform to the general rules of nomenclature, still we believe
that names currently used in bacteriologic literature, as gonococcus, pneumococ-
cus, staphylococcus, tubercle bacillus, diphtheria bacillus, can still be used, but
as so-called ordinary names. Thus the technical botanist, if not speaking in a
strictly systematic sense, often speaks of oak instead of Quercus, and strawberry
instead of Fragaria. We must, however, strictly avoid smuggling into the liter-
ature as names of genera, such names as gonococcus, etc.

Comment. Migula in his monumental treatise on bacteria published
in 1900, and Chester in his Manual of Determinative Bacteriology
published in 1901 have both followed with a measurable degree of suc-
cess, the rules which have been so clearly summarized in the above
statement by Lehmann and Neumann. These rules are, of course, as
the authors have indicated, only a condensed summary of international
rules with a few interpolations of the authors themselves. In an
extensive discussion or consideration of nomenclature, questions are
constantly arising which can not be answered by this summary. It is
necessary for sufficient and adequate information as to their solution,
to turn to the international rules which govern botanical nomenclature.

GENERAL SYSTEMATIC BACTERIOLOGY 113

B. INTERNATIONAL RULES OF BOTANICAL NOMENCLATURE

On the following pages the botanical code (or international rules)
as revised by the Brussels International Botanical Congress of 1910,
is given in detail. In some cases the discussions given in the original
rules under the heading of Examples, has been abbreviated, as many of
the examples deal with problems not faced by the bacteriologist. In
certain cases rules and recommendations have been omitted for the
same reason. A paragraph headed "Comments" is added in many
cases to point out certain applications in the field of bacteriology'. In
some cases comparisons with similar or antagonistic provisions in the
zoological code are made. It will be evident as one studies these rules
that the botanical code was drafted with the vascular plants in mind
and most of the illustrations in consequence have been drawn from this
field. However, it has been emphasized previously that a study of the
various provisions will show that with but few exceptions they are
equally applicable to the conditions which confront the bacteriologist.

Chapter I. General considerations and leading principles

Article 1. Natural history can make no progress without a regular system of
nomenclature, which is recognized and used by the great majority of naturalists
in all countries.

Comment. Apparently about 900 names have been proposed by vari-
ous authors for genera and higher groups of bacteria up to 1924. Several
thousand species have been named. However, it is probable that not
one species in ten has been adequately described or named. It is
evident that unless an effort is made to follow some system that the same
name will be applied to many different kinds of bacteria, and many
names to a single kind.

Article 2. The prescriptions which govern the exact system of botanical
nomenclature are divided into principles, rules and recommendations. The prin-
ciples (art. 1-9, 10-14 and 15-18) are the foundation of the rules and recommen-
dations. The rules (art. 10-58), destined to put in order the nomenclature which
has bequeathed to us, and to form the basis for the future, are always retroactive :
names or forms of nomenclature which are contrary to a rule cannot be main-
tained. Recommendations bear on secondary points, their object being to ensure
for the future a greater uniformity and clearness in nomenclature ; names or forms
of nomenclature contrary to a recommendation are not a model to copy, but
cannot be rejected.

Article 3. The rules of nomenclature should neither be arbitrary nor imposed
by authority. They must be simple and founded on considerations clear and
forcible enough for everyone to comprehend and be disposed to accept.

114 GENERAL SYSTEMATIC BACTERIOLOGY

Comment. It may be emphasized that the International Botanical
Congresses which have formulated and revised the International Code
have no power to enforce these rules. Stiles (1905, p. 9) states the
matter succinctly in his discussion of the zoologist's code. He says:

Every person is still in a position to follow any code he desires, or to prepare
one of his own, but, considering the responsibilities involved, there is undoubtedly
a growing tendency to adopt the International Code. Further, it is considered
ethical to ignore names used contrary to this and to other standard codes. While
not attempting to dictate to men of science what they shall or shall not do, the
commission submits the rules to the serious consideration of all workers in the
spirit advanced by Strickland (1842), namely, "we offer them to the candid con-
sideration of zoologists in the hope that they may lead to sufficient uniformity of
method in future to rescue science from becoming a mere chaos of words."

Article 4. The essential points in nomenclature are: (1) to aim at fixity of
names; (2) to avoid or to reject the use of forms and names which may cause
error or ambiguity or throw science into confusion.

Next in importance is the avoidance of all useless creation of names.

Other considerations, such as absolute grammatical correctness, regularity or
euphony of names, more or less prevailing custom, respect for persons, etc., not-
withstanding their undeniable importance are relatively accessory.

Article 5. No custom contrary to rule can be upheld if it leads to confusion or
error. When a custom offers no serious inconvenience of this kind, it may be a
ground for exceptions which we must, however, abstain from extending or copy-
ing. Finally in the absence of rule, or where the consequences of rules are doubt-
ful, established custom becomes law.

Comment. This general principle is a useful guide in certain puz-
zling situations, and is a distinct help toward stability. For example.
Article 21 of the code specifies that families are to be designated by the
name of one of their genera or ancient generic name, with the ending
-aceae. The family name Coccaceae has been quite generally used in
bacteriology during the past two decades. There is, however, no
valid, or strictly speaking, any ancient, bacterial genus Coccus in bac-
teriology. Nevertheless it is probably advisable to make this family
name the basis of an exception, as such exception would quite certainly
cause less confusion than the adoption of an entirely new designation.

Article 6. The principles and forms of nomenclature should be as similar as
possible in botany and in zoology; but botanical nomenclature is entirely inde-
pendent of zoological nomenclature.

Comment. The zoological code is somewhat more specific than is
the botanical code in dealing with this problem. The corresponding
article in the zoological rules reads as follows :

GENERAL SYSTEMATIC BACTERIOLOGY 115

Zoological nomenclature is independent of botanical nomenclature in the sense
that the name of an animal is not to be rejected simply because it is identical to a
name of a plant. If, however, an organism is transferred from the vegetable to
the animal kingdom its botanical names are to be accepted in zoological nomen-
clature with the original botanical status; and, if an organism is transferred from
the animal to the vegetable kingdom its names retain their zoological status.

The following recommendation is also added: "It is well to avoid
introducing into zoology as generic names, such names as are in use in
botany." These points are of interest to the bacteriologist because
until the suggestion was made in 1857 by Naegeli that bacteria are
plants and not animals, most of the forms up to that time described
which we now classify with the bacteria, had been included with the
protozoa. This means that such names as Bacterium, Spirillum,
Spirodiscus, Spirochaeta, and Vibrio were included. In the classifica-
tion of Cohn (1872) these forms were definitely transferred to the plant
kingdom. Thej- have been used in both zoological and botanical tenni-
nolog}', and, therefore, they prevent subsequent use of these names
for other forms among either plants or animals. However, the fact
that Coccus is the name of a genus of insects would not interfere with
its use as a genus in bacteriology. Neither does the fact that Spirillum
was used in 1815 as the name of a worm prevent its acceptance as a
valid genus of bacteria. Numerous examples might be cited of generic
names which are identical in zoology and botany. It is well, however,
to avoid the introduction of names used as genera of animals into
botany when possible. This is particularly true in bacteriology, for
many of the types have an uncertain position. The group of spiro-
chetes, for example, is treated both by bacteriologists and protozoolo-
gists. To introduce a generic name into this group under the impres-
sion that it belongs w^th plants when such a name has previously been
used in zoology, is to cause unnecessary confusion and may very possibly
invalidate the name. In a few instances organisms have been named as
plants and later found to be animals. Stiles (1905, p. 10) states:

In these cases zoologists accept the botanical names, thus Plasmodium malariae
was originally (1881) classified in a plant genus as Oscillaria malariae. Now that
this organism is classified as an animal the original specific name malariae (1881)
is accepted in zoology with its original botanical date. The generic name
Oscillaria is not taken over with the specific name because it was not proposed for
this organism. Oscillaria remains as it was prior to 1881, a plant genus.

Article 7. Scientific names are in Latin for all groups. When taken from
another language, a Latin termination is given them, except in cases sanctioned by
custom. If translated into a modern language, it is desirable that they should
preserve as great a resemblance as possible to the original Latin names.

116 GENERAL SYSTEMATIC BACTERIOLOGY

Comments. This rule has been too frequently disregarded by bac-
teriologists. In many cases this has come about through failure of the
one who first described an organism to give to it a specific name, or one
in the correct form. For example, Duclaux (1882) described an organ-
ism which he found associated with the production of slimy or ropy milk.
This he placed in his genus Actinobacter but without giving it a specific
name. In consequence this organism is commonly noted in literature
as Actinobacter du lait visqueux Duclaux, an impossible combination.
German writers furthermore have frequently changed the spelling of
Latin words from their Latin form, as Bacterium to Bakterium, Bacil-
lus to Bacillus, Streptococcus to Streptokokkus, in order to use them as
vernacular designations. In many cases after having accepted this
changed spelling, the fact is ignored that they have lost their status as
generic names and the words are used as though they were in correct
Latin form, as in the name Staphylokokkus pyogenes. German, French
and Italian authors have also shown a tendency to change the names of
families and of whole groups, from their correct Latin form, and yet con-
tinue to use them in a scientific and not merely a vernacular sense, as
Arthrobakteriaceen for Arthrobacteriaceae, Kokkaceen and Coccacees for
Coccaceae.

Article 8. Nomenclature comprises two categories of names: (1) Names, or
rather terms, which express the nature of the groups comprehended one within
the other. (2) Names peculiar to each of the groups of plants that observation
has made known.

Comments. The nature of the names noted under 1 and 2 will be
evident after a perusal of Chapters II and III respectively in which
these are discussed.

Article 9. The rules and recommendations of botanical nomenclature apply to
all classes of the plant kingdom, reserving special arrangements for fossil plants
and non-vascular plants.

Comments. A footnote to the code of 1905 states that the special
arrangements noted were to be taken up at the next International
Botanical Congress in 1910. These arrangements included "(1) Rules
bearing on special points in relation to the nature of fossils or lower
plants. (2) Lists of nomina conservanda for all divisions of plants other
than Phanerogams." At this meeting several rules relating primarily
to paleobotany and to the algae, fungi, hepatics, lichens and mosses
were adopted, but the question of the date of departure and other ques-
tions relating to the bacteria and certain other groups were reserved for
the International Congress which was to have met in London in 1915.

GENERAL SYSTEMATIC BACTERIOLOGY 117

It is evident that this principle makes possible the recommendation
and adoption of special rules to govern groups such as the bacteria.
Some such special rules have been suggested to the Society of American
Bacteriologists through its committee on bacterial classification.

Chapter II. On the manner of designating the nature and the sub-
ordination of the groups which constitute the plant kingdom

Article 10. Every individual plant belongs to a species (species), every species
to a genus (genus), every genus to a family (familia), every family to an order
(ordo), every order to a class (classis), every class to a division (divisio).

Article 11. In many species we distinguish varieties (varietas) and forms
(forma); and in some cultivated species, modifications still more numerous; in
many genera sections (sectio), in many families tribes (tribus).

Article 12. Finally if circumstances require us to distinguish a greater number
of intermediate groups, it is easy, by putting the syllable sub before the name of a
group, to form subdivisions of that group. In this way subfamily (subfamilia)
designates a group between a family and a tribe, subtribe (subtribus) a group be-
tween a tribe and a genus, etc. The arrangement of subordinate groups may thus
be carried, for wild plants only, to twenty-one degrees, in the following order:
Regnum vegetabile, Divisio, Subdivisio, Classis, Subclassis, Ordo, Subordo,
Familia, Subfamilia, Tribus, Subtribus, Genus, Subgenus, Sectio, Subsectio,
Species, Subspecies, Varietas, Subvarietas, Forma, Individuum.

If this list of groups is insufficient it can be augmented by the intercalation of
supplementary groups, so long as these do not introduce confusion or error.

Example : Series and Subseries are groups which can be intercalated between
subsection and species.

Recommendation. I. In parasites, particularly in parasitic fungi, authors who
do not recognize as species forms which are characterized from a biologic point of
view, but little or not at all from the standpoint of morphology may differentiate
within species special forms (forma specialis, f. sp.) characterized by their adap-
tation to their different hosts.

Article 13. The definition of each of these names of groups varies, up to a cer-
tain point, according to individual opinion and the state of the science, but their
relative order, sanctioned by custom must not be altered. No classification is
admissible which contains such alterations.

Examples of inadmissible alterations are — a form divided into varieties, a
species containing genera, a genus containing families or tribes.

Article 14. The fertilization of one species by another gives rise to a hybrid
(hybrida), that of a modification or subdivision of a species by another modifica-
tion to the same species gives rise to a half-breed (mistus, mule of floristis).

Chapter III. On the manner of designating each group or associa-
tion of plants

Section 1. General 'principles; priority

Article 15. Each natural group of plants can bear in science only one valid
designation, namely, the oldest, provided that it is in conformity with the rules
of Nomenclature and the conditions laid down in articles 19 and 20 of section 2.

lis GE.Ni:iv.\L SYSTEMATIC BACTEKIOLOGY

Comment, lliis is tho essence of the whole matter. Xo matter what
our individual preferences may lx\ or how umch better aiiotiier moiv
familiar name may soimd, we sliould choose the oldest name if it is
valid. In no other way can nomenclature be stabilized. Many cases
in bacteriological literatui-e may be cited in Mliich author have
created new names needlessly, in some cases because the names seemed
inappropriate for some ivason.

Article 16. The designation of a group by one or several names is not for the
purpose of describing the characters or the history of the group, but that we may
be understood when we wish to speak of it.

ComnietU. ^Misunderstanding of this principle has led to uuuiy mis-
takes in literature. Thei-e is no good reason why the specific name of
an organism must Iv descriptive of the organism in any way. Some
authors have contended that the naming of X)rganisms sliould in some
manner confonn to the principles which have been followed in the
naming of compounds in the science of chemistry. Othei-s have insisted
upon the use of descriptive Latin phrases, such as those which have
been approved in anatomy and pathology-. As has often been pointed
out in taxonomic discussioi^s.thei*e is no more reason why a specific name
should be descriptive of the organisms than that the given or Christian
name of an individual should indicate his characteristics.

Article 17. Xo one should change a name or a combination of names without
serious motives, based on a more profound knowledge of facts, or on the necessity
of giving up a nomenclature that is contrary to rules.

Comment. Unfortunately there have been a few botanists, perhaps
even some bacteriologists who have coined new names needlessly,
evidently with the thought that such could in some way be of pei-sonal
advantage. It is evident from the statement of this rule that when new
names are coined or old names changed, an adequate reason for such
new names or such new t.enns should Ix' given.

Article 18. The form, number and arrangement of names depend on the
nature of each group, according to the following rules.

Section .:?. Point of departure for nomenclature; litnitaiion of principle of

priority

Article 19. Botanical nomenclature begins for the various groups of plants
(both living and fossil) with the following dates:

a. Phanerogamae and Pteridophyta, 1753 (Linn^., Species plantarum, ed. 1)

b. Muscineae, ISOl (Hedwig, Species Muscorum)

OESTERAL snTKTEMATlC BACTtJilOUKiT 119

c. HepfUicoe and Hphagnaceae, 17.93 (Luui^., Bpee i ta frfantamm e<L 1 j

d. JAr^hene*, 1753 /^Liim6,, Species pUatafimi, ed. 1>

e. Fungi: {,'re/lirt/dei, VitiUigiiude$ and Ga»ter»myeeiet, 1801 (Penofju,

Syiwpeia Mfethodica Funi^omm)

f. /'ttn^' cael^i, 1^521-32 ''Fries, Systema Mjcolog^eam)

g. Algae, 1753 (Linu^., Species plantanun edL 1)

KzcfrptioDs: Notiloeaceae hrnnocyiteatf 1^(02-98 (Gomont, Nostoeaeeaehomo-
cynUae,; NotUtcaceae heUrocysileae, 1S86 CBoraet and FUUiaolt, 3ro»-
loTMce^ie heteroey$teae); De^tmidiaceae, 1S48 (R^fs, British Demudiaeeae) ;
Oedogordaeeae, 1900 (Him, Monographie and leonographie der
Oedogoniaceen ji
h. Myzomycdefi, 1753 'Xinn^., G«iera plantamm, ed. 1)
It is agreed to associate genera, the names of whieh appear in the hrst edition
of iSpecies Flantamm of Linn^ with the descriptions iihieh he has given in his
Genera Plantanun, ed. 5 (1754).

Comment. A footnote to this sutide iji the Proceednigs of the
Bnjfjsels Ckmgrese in 1910 states, "The points of departure for the
nomenclature of the following groups: Schizr/myc^ie^ (Bacteria); Schiz-
f/jjhycf/ie (excl. Xoiitocaceae); Flagellalae (inch DtrioflageUatae) and
Ba/dllarryiceae (Diatomaceae) are reserved for the Congress of
London in 1915." This Congress was postponed because of the
interruption by the European War. Tliere Ls therefore no authori-
tative starting point for Vmcterial nomenclature at the present time.
At this Congress in Brussels Vuillemin proposed that 1753 be adopted
as the point of departure. Klebahn suggested that the work of F.
Cohn C 1870-76, Untersuchungen uber Bakterien) con.«tituted a more
suitable point of departure. This was approved bj- Engler. Magnus
contended that much work of systematic value had been accomplished
before 1870 and proposed that the pubh cations of Ehrenbei^ (certainly
a misprint) in 1786 should be the starting point. Vuillemin contended
that if a date subsequent to 1753 l>e taken, it might well be 1910. The
whole matter was finally deferred to the next Congress as noted above.

In preparation for this Congress Vuillemin ri913; published a paper
in which ho discussed bacterial classification and nomenclature. He
concluded that the best thing to do is to determine which generic names
are valid, prepare such a list, publish the names as genera conservanda
and date all bacterial classification from 1915 when the list was to have
IjfifiU adopted by the Congress. A study of Vuillemin's paper despite
his criticism of bacteriologists as taxonomists shows that he himself
does not formulate tenable bases for differentiation of genera and his
reason for choosing certain generic names and abandoning others vi-ill
scarcely withstand critical analysis.

120 GENERAL SYSTEMATIC BACTERIOLOGY

The committee on classification of the Society of American Bacteri-
ologists has suggested that the publication of the third edition of
Zopf's "Die Spaltpilze" in 1885 be made the point of departure. Unex-
pected difficulties in the utilization of 1885 as the point of departure
have arisen. It seems probable that the least confusion will eventually
develop if 1753 be regarded as the date of departure.

Article 20. However, to avoid disadvantageous changes in the nomenclature
of genera by the strict application of the rules of nomenclature, and especially
of the principle of priority in starting from the dates given in Article 19, the rules
provide for lists of names which must be retained in all cases. These names are
by preference those which have come into general use in the fifty years following
their publication, or which have been used in monographs and important floristic
works up to the year 1890. For the use of paleobotanists two lists are provided
(1) A list of generic names validly published and generally accepted, although
they come into conflict with paleobotanic names which are older. (2) A list of
generic names of fossil plants, validly published and generally accepted when
they come into conflict with older homonyms of living plants which have been
discarded into synonymy. In order to avoid using these names anew, these lists
are given in an appendix to the rules of nomenclature.

Comments. Two lists of generic names have been proposed for
eventual submission to an International Botanical Congress for use in
bacteriology. The first of these was published by Vuillemin (1913)
and is as follows : Planococcus, Streptococcus, Klebsiella, M crista, Plano-
merista. Neisseria, Sarcina, Planosarcina, Metahacterium, Clostridium,
Serratia, Bacterium and Spirillum.

In 1916 the following list of genera was proposed to the Society of
American Bacteriologists by its committee on classification. These
names were to be considered for two years before a vote should be taken
upon them. The list is as follows: Methanomonas, Carboxydomonas,
Hydrogenomonas, Mycoderma, Nitrosomonas, Nitrobacter, Azotobacter
Rhizobium, Nocardia, Actinomyces, Mycobacterium,, Corynebacterium,
Fusiformis, Leptotrichia, Pseudomonas, Vibrio, Spirillum, Neisseria,
Streptococcus, Staphylococcus, Albococcus, Micrococcus, Sarcina, Rhodo-
coccus, Bacterium, Erwinia, Pasteurella, Hemophilus, Lactobacillus,
Bacillus, Clostridium. More recent study shows that probably this
list should be revised.

Section 3. Nomenclature of the different kinds of groups
Subsection 1. Names of groups above the family

Recommendations. The following suggestions as to the nomenclature of
groups of higher rank than the family will tend to clearness and uniformity.

GENERAL SYSTEMATIC BACTERIOLOGY 121

II. Names of divisions and subdivisions, of classes and subclasses are taken
from one of their chief characters. They are expressed by words of Greek or Latin
origin, some similarity of form and termination being given to those that desig-
nate groups of the same nature.

III. Orders are designated preferably by the name of one of their principal
families, with the ending -ales. Suborders are designated in a similar manner,
with the ending -ineae. But other terminations may be retained for these names,
provided that they do not lead to confusion or error.

Comment. The generally accepted name for the entire group of bac-
teria is Schizomycetes. This may be regarded as a class. The preferable
designation for the orders of bacteria would have the ending -ales. The
committee on classification of the Society of American Bacteriologists
has suggested the following four orders : Myxobacteriales, Thiobaderiales,
Chlamydobacter tales and Eubacteriales.

Subsection 2. Names of families and subfamilies, tribes and subtribes

Article 21. Families (Jamiliae) are designated by the name of one of their
genera or ancient generic names with the ending -aceae.

Examples: Rosaceae (from Rosa), Salicaceae (from Salix), Caryophyllaceae
(from Dianthus Caryophyllus), etc.

Comment. Among the family names of bacteria which have been
proposed and which are in correct form are : Spirillaceae from Spirillum,
Bacteriaceae from Bacterium, Bacillaceae from Bacillus.

Examples of invalid families in. bacteriology are the following : Thio-
bacteriaceae, because there is no genus Thiobacterium, Thiorhodaceae
because there is no genus Thiorhodum, Trichobacteria, both because it
lacks the ending -aceae and because it contains no genus Trichobacterium.

Article 22. The following names, owing to long usage, are an exception to the
rule: Palmae, Gramineae, Cruciferae, Leguminosae, Guttiferae, Umbelliferae,
Labiatae, Compositae.

Article 23. Names of subfamilies (subfamiliae) are taken from the name of one
of the genera in the group, with the ending -oideae. The same holds for the
tribes (tribiis) with the ending -eae, and for the subtribes (subtribus) with the
ending -inae.

Comment. The following subfamilies of bacteria are in proper form:
Chromatioideae from the genus Chromatium, Rhodobacterioideae from the
genus Rhodobacterium. The following are examples of names of sub-
families incorrectly formed: Paracoccaceae and Metacoccaceae because
there are no bacterial genera Paracoccus and Metacoccus, and also
because of an incorrect ending. An example of a tribal name would be
Streptococceae containing the genus Streptococcus; of a subtribe, Bacil-
linae containing the genus Bacillus.

122 GENERAL SYSTEMATIC BACTERIOLOGY

Subsection 3. Names of genera and divisions of genera

Article 24. Genera receive names, substantives (or adjectives used as sub-
stantives) in the singular number and written with a capital letter, which maybe
compared with our own family names. These names may be taken from any
source whatever and may even be composed in an absolutely arbitrary manner.

Examples: Rosa, Convolvulus, Hedysarum, Bartramia, Liquidambar, Gloriosa,
Impatiens, Manihot.

Comments. Examples of bacterial genera are Bacillus, Actinom.yces
and Vibrio.

Not infrequently, particularly in medical writers, one finds a decided
tendency to ignore the rule that a genus name must, when used as such,
always be written with a capital letter. Many of our medical journals
and even some which publish scientific articles on medical bacteriology'
write bacillus typhosus or bacillus tuberculosis. It is true that sometimes
a word with the same spelling as a generic name may be used as a
morphologic designation. It cannot be considered incorrect to speak
of tubercle bacillus, for this is a common name or vernacular designation.
As Stiles (1905, p. 16) says: (this same rule holds in zoological
nomenclature)

This custom of capitalizing the generic name has come down to us from former
centuries, and while it now has its practical basis, its historic basis is probably due
to the custom earlier authors had of capitalizing all Latin substantives when used
in nomenclature. At present the custom is so thoroughly established that bota-
nists and zoologists experience much the same sensation in seeing "bacillus
tuberculosis" or "plasmodium malariae," instead of Bacillus tuberculosis and
Plasmodium malariae. that they would if they found a reference to "american"
authors or to "doctor s. weir mitchell."

It is also considered good form to write names of genera, particularly
when associated with a specific name, in italics. Some of our medical
journals have recentlj^ abandoned this practice under the plea that
it is an unnecessary expense and that italics should be used only for
the sake of emphasis. This is unfortunate as it has in the past served
as a satisfactory method to indicate clearly in a text just when names
were being used in a strict scientific sense.

Some purists have taken exception to the statement that these names
may be taken from any source whatever and may even be composed in
an absolutely arbitrary manner. Clements (1902) in his paper on Greek
and Latin in biological nomenclature states that vernacular names
should be invalid, and that a name or term should be regarded as invalid
unless constructed according to the principles of word formation in

GENERAL SYSTEMATIC BACTERIOLOGY 123

classic Greek or Latin; and all terms improperly constructed should be
corrected. He further states that anagrams and geographic names
should be regarded as invalid for genera.

Below under the heading of ''Recommendations" there are many-
suggestions of the best form to follow in the creation of generic names,
but failure to follow such recommendations does not render a term
invalid.

Article 25. Subgenera and sections also receive names, usuallj' substantives
and resembling the names of genera. Names of subsections and other lower sub-
divisions of genera are preferably adjectives in the plural number and written
with a capital letter, or their place may be taken by an ordinal number or a letter.

Examples: Substantives: Fraxinaster, Trifoliastrum, Adenoscilla, Euher-
mannia, Archieracium, Micromelilotiis, Pseudinga, Heterodraba, Gymnocimum,
Neoplantago, Stachyotypus. Adjectives: Pleiostylae, Fimbriati, Bibracteolata,
Pachycladae.

Comments. Among names that have been applied to subgenera of
bacteria are Eusarcina and Euspirillum.

Recommendations. IV. When the name of a genus, subgenus or section is
taken from the name of a person, it is formed in the following manner:

a. When the name ends in a vowel, the letter a is added (for example Glazioua
Gtaziou; Bureaua after Bureau), except when the name already ends in a, in
which case ea is added (e.g., Collaea after Colla).

b. When the name ends in a consonant, the letters ia are added (thus Mag-
nusia after Magnus; Ramondia after Ramond), except when the name ends
in er, in which case a is added (e.g., Kernera after Kerner).

c. The spelling of the syllables unaffected by these finals is retained, even
with the consonants k and w or with groupings of vowels which were not used in
classic Latin. Letters which are unknown to botanical Latin must be transcribed,
diacritic signs are suppressed. The German a, 6, li, become ae, oe, ue, the French,
6, e and e become generally e.

d. Names may be accompanied by a prefix, or a suffix, or modified by anagram
or abbreviation. In these cases they count as different words from the original
name. E.g., Durvillea and Urvillea, Lapeyroxisea and Peyrousea, Englera,
Englerastrum and Englerella, Bouchea and Ubochea, Gerardia and Graderia,
Martia and Martiusia.

Comments. Among the generic names of bacteria which have been
derived from patronymics are Pasteurella, Salmonella, Klebsiella, Detoni-
ella, Zopfiella, Mantegazzaea, Erwinia, Pacinia, Cornelia, Newskia,
Pollendera, Macintoshillus, Metchnikovillus, ZopfiuSi It will be noted
that authors have frequently given generic names among the bacteria
by adding -ella in accordance with above. The custom is so well estab-
lished that there would seem to be little good reason at the present time

124 GENERAL SYSTEMATIC BACTERIOLOGY

for opposing it. There have been objections, however, raised by those
who contend for the use of classic Latin names for all plants and animals.
Clements (1902, p. 82) says: "A single generic name may be founded
upon the name of a botanist. Such names are only to be formed by
adding -ia to cognomina ending in a consonant and -a to cognomina in
a vowel or in -r except in the case of names already latinized in which
case the termination is first dropped." Apparently Clements possessed
a high estimate of the ability of classic Latin and Greek to furnish the
tens of thousands of generic names that will still be demanded before
all plants and animals have been named and classified. The formation
of names by anagram is also objectionable to such purists, as witness
the following statement from Clements (1902, p. 78):

Anagrams if they be considered words at all are vernacular since they are
neither Greek or Latin. They are the ultimate product of puerility or illiteracy
in nomenclature. Such a series as Filago, Gifola, Ifloga, Logfia and Oglifa throws
a clear light upon the good sense and linguistic tests of the authors concerned.
One might better make names after the fashion of Carroll or take names from
the "dog latin" of childhood.

Views in contradiction to this are generally held, however, by most
practical workers in the fields of zoology and botany. These workers
have a firm conviction that botanical Latin does not need to be classic
Latin. This is well stated in the following quotation from Stiles (1905,
p. 12):

Nothing is stated in the rule as to what particular Latin should be used, but
latitude is granted to use Latin or Latinized names, or to use names as if they
were Latin. This latitude has its practical basis. The Latin poets and authors
did not foresee the practical scientific use to which their language would be
applied, and they failed to leave enough Latin words as names for the millions of
animals and plants which come into consideration. Hence as a carpenter, a
sailor or a manufacturer coins words which are accepted in English as English
words of good standing, when applied to carpentry, nautical affairs, and trade, the
zoologists and botanists coin words upon Latin precedents, which we adopt as
botanical and zoological Latin. Not in all cases do our efforts attain the highest
standards of classical Latin (Taenia solium., and Gadus tomcod, for instance),
but because of practical considerations such names are retained, although not
recommended, as examples to be followed in coining new words.

V. Botanists who are publishing generic names show judgment and taste by
attending to the following recommendations:

a. Not to make names very long or difficult to pronounce.

Comments. Clements believes that a generic name should be invalid
if it contains more than six syllables. Apparently few generic names

GENERAL SYSTEMATIC BACTERIOLOGY 125

have been applied to bacteria which do not conform to this standard,
though there are many with six syllables such as Botulobacillus, Actino-
bacillus, Actinocladothrix, Aphaneroglia and Arthrohactrinium. Some
offenders are the following: Actinohacterium, Caseobaderium, Chromo-
beggiatoa, Corynebacterium, Liquidobacterium and Nitrosobacterium.
These long names are, of course, valid.

b. Not to use again a name which has already been used and has lapsed into
sjrnonymy (homonym).

Comments. The zoological code goes farther than this and forbids
the subsequent use for another group of any name which has previously
been used. The rule reads "A generic name is to be rejected as a homo-
nym when it has previously been used for some other genus of
animals."

c. Not to dedicate genera to persons who are in all respects strangers to botany,
or at least to natural science, nor to persons quite unknown.

d. Not to take names from barbarous tongues, unless those names are frequently
quoted in books of travel, and have an agreeable form that is readily adapted to
the Latin tongue and to the tongues of civilized countries.

e. To recall, if possible, by the formation or ending of the name, the aflanities
or the analogies of the genus.

f. To avoid adjectives used as nouns.

g. Not to give a genus a name whose form is rather that of a subgenus or section
(e.g., Eusideroxylon, a name given to a genus of Lauraceae, which, however,
being valid, cannot be changed).

Comment. The Eubacillus of Dangeard is a similar example from
bacteriology'.

h. Not to make names by the combination of two languages {nomina hybrida).

Comments. This is a common fault among names which have been
appUed in bacteriology. Among such may be noted Acetobacter, Caseo-
bacterium, Coccobacillus.

VI. Botanists constructing names for subgenera or sections, will do well to at-
tend to the preceding recommendations and also to the following :

a. Give, where possible, to the principal division of a genus, a name which,
by some modification or addition, calls the genus to mind (for instance, Eu placed
at the beginning of the name, when it is of Greek origin; -astrum, -ella at the end
of the name, when Latin, or any other modification consistent with the grammar
and usages of the Latin language).

b. Avoid calling a subgenus or a section by the name of the genus to which it
belongs, with the final -oides or -opsis; on the contrary reserve this ending for a

126 GENERAL SYSTEMATIC BACTERIOLOGY

section which resembles another genus, by adding in that case -aides or -opsis to
the name of that other genus, if it is of Greek origin, to form the name of the
section.

0. Avoid taking as the name of a subgenus or section a name which is already
in use as such in another genus, or which is the name of an admitted genus.

Comment. It may be noted that in zoology identical rules are used
for the formation of genera and subgenera, because the subgenus of
today maybe the genus of tomorrow and, from the standpoint of nomen-
clature, both generic and subgeneric names have the same status.
Unfortunately, perhaps, botanists have not seen fit to take this step.

Recommendation. VII. When it is required to express a subgeneric or sectional
name together with the name of the genus and the name of the species, the name
of the section is put between the others in a parenthesis. E.g., Astragalus
(Cycloglottis) contortuplicatus .

Subsection 4. Names of species and of subdivisions of species

Article 26. All species, even those that singly constitute a genus, are desig-
nated by the name of the genus to which they belong followed by a name (or
epithet) termed specific, usually of the nature of an adjective (forming a combina-
tion of two names, a binomial, or binary name).

Recommendations. VIII. The specific name should, in general, give some
indication of the appearance, the characters, the origin, the history or the proper-
ties of the species. If taken from the name of a person, it usually recalls the
name of the one who discovered or described it, or was in some way concerned
with it.

Comment. Apparently this recommendation is sometimes taken to
indicate that the specific name should constitute an adequate diagnosis
of the organism in question.

IX. Names of men and women and also names of countries and localities used
as specific names, may be substantives in the genitive (Clusii, saharae) or adjec-
tives (Clusianus, dahuricus) . It will be well, in the future, to avoid the use of the
genitive and the adjectival form of the same name to designate two different
species of the same genus, for example Lysimachia Hemsleyana Maxim (1891),
and L. Hemsleyi Franch (1895).

X. Specific names begin with a small letter except those which are taken from
names of persons (substantives or adjectives) or those which are taken from
generic names (substantives or adjectives).

XI. When a specific name is taken from the name of a man, it is formed in the
following way:

a. When the name ends in a vowel, the letter i is added (thus Glazioui from
Glaziou; Bureaui from Bureau), except when the name ends in a, when e is added
(thus Balansae from Balansa).

GENERAL SYSTEMATIC BACTERIOLOGY 127

b. When the name ends in a consonant, the letters ii are added (thus Magnitsii
from Magnxis: Ramondii from Ramond), except when the word ends in er when i
is added (ex. Kerneri, from Kerner).

c. Syllables which are not modified by these endings retain their original spell-
ing, even in the case of the consonants k and w or groupings of vowels which are
not used in classic Latin. Letters foreign to the Latin of botanists should be
transcribed, and diacritic signs suppressed. The German a, 6, ii, become ae, oe,
ue, the French e, e and e become, in general, e.

d. When specific names taken from the name of a person have an adjectival
form a similar plan is adopted {Geranium Roberiianum, Car ex Holler ana, Ranun-
culus Bureauanus, etc.).

Xn. The same applies to the names of women. These are written in the
feminine when they have a substantival form.

Example: Cypripedium Hookerae, Rosa Beatricis, Scabiosa Olgae, Omphalodes
Luciliae.

XIII. In the formation of specific names composed of two or several roots and
taken from Latin or Greek, the vowel placed between the two roots becomes a
connecting vowel, in Latin i, in Greek o; thus we write menthifolia, salviifolia, not
menthaefolia, salviaefolia. When the second root begins with a vowel and
euphony demands, the connecting vowel is eliminated (e.g., calliantha, lepidan-
tha). The connecting ae is legitimate only when etymology demands (e.g.,
caricaeformis from Carica, may be retained along with cariciformis from Carex).

XIV. In forming specific names, botanists will do well to note the following
recommendations :

a. Avoid very long names and those which are difficult to pronounce.

Comments. A few specific names vi^hich have been applied to bacteria
seem to transcend good usage, but this of course does not invaHdatethem.
Among such long specific names which have been applied may be noted
the following: saccharobutyricus, heminecrobiophilus, diphtheriae-colum-
horum, viridi-pallescens, endoparagocicum, melanoglassophorus.

b. Avoid names which express a character common to all or nearly ail the
species of a genus.

Comment. Among such names are the followiag: Streptococcus
sphericus and Albococcus albus. These names ane, of course, valid.

c. Avoid names taken from little known or very restricted localities, unless
the species be very local.

Comment. Azotobacter vinelandii named after a locality in New
Jersey is scarcely in conformity with this recommendation, but is, of
course, not invalidated by this fact.

d. Avoid, in the same genus, names which are very much alike, especially
those which differ only in their last letters.

128 GENERAL SYSTEMATIC BACTERIOLOGY

e. Adopt unpublished names found in travellers' notes and herbaria, attribut-
ing them to the authors concerned, only when those concerned have approved the
publication.

f . Avoid names which have been used before in the genus, or in any closely
allied genus, and which have lapsed into synonymy (homonyms).

Comment. The Zoological Code reads: "A specific name is to be
rejected as a homonym when it has previously been used for some other
species of the same genus." This recommendation should as far as
practicable be given the force of a rule.

g. Do not name a species after a person who has neither discovered, nor
described, nor figured, nor in any way studied it.

h. Avoid specific names formed of two words.

Comment. Bacillus acidi lactici is probably valid inasmuch as the
specific name refers to a single concept, but it is not a form to pattern
after. This, of course, does not validate such a name as Bacillus coli
communis, which is a trinomial.

Article 27. Two species of the same genus cannot bear the same specific name,
but the same specific name may be given in several genera.

Example : Arabis spathulata DC. and Lepidium spathulatum Phil, are valid as
two names of Crucifers; but Arabis spathulata Nutt. in Torr. and Gray cannot be
maintained, on account of the existence of Arabis spathulata DC, a name previ-
ously given to another valid species of Arabis.

Article 28. Names of subspecies and varieties are formed like specific names
and follow them in order, beginning with those of the highest rank. The same
holds for subvarieties, forms, and slight or transient modifications of wild plants
which receive a name or numbers or letters to facilitate their arrangement. Use
of a binary nomenclature for subdivisions of species is not admissible.

Examples: Andropogon ternatus subsp. macrothrix (not Andropogon macro-
thrix or Andropogon ternatus subsp. A. macrothrix) ; Herniaria hirsuta var. diandra
(not Herniaria diandra or Herniaria hirsuta var. H. diandra) ; forma nanus, forma
maculatum.

Recommendation. XV. Recommendations made for specific names apply
equally to names of subdivisions of species. These agree with the generic name
when they have an adjectival form {Thymus Serpyllum var. angustifolius, Ranun-
culus acris subsp. Friesianus).

Special forms are named by preference by means of the names of the host
species. In making such names one may employ double names. Examples:
Puccinia Hieracii f. sp. villosi, Pucciniastrum Epilobii f. sp. Abieti-Chamaenerii.

Article 29. Two subspecies of the same species cannot have the same name.
A given name can only be used once for a variety of a given species, even when
dealing with varieties which are classed under different subspecies. The same
holds for subvarieties and forms.

On the other hand the same name may be employed for subdivisions of different
species, and the subdivisions of any one species may bear the same name as other
species.

GENERAL SYSTEMATIC BACTERIOLOGY 129

Examples: The following are admissible: Rosa Jundzillii var. leioclada and
Rosa glutinosa var. leioclada; Viola tricolor var. hirta, in spite of the existence
already of a diffeient species named Viola hirta. The following are incorrect:
Erysimum hieraciifolium subsp. strictum var. longisiliquum and E. hieraciifolium
subsp. pannonicum var. longisiliquum — a form of nomenclature which allows two
varieties bearing the same name in the same species.

Recommendation. XVI. Botanists are recommended to use as little as possible
the privilege granted in the second part of article 29, in order to avoid confusion
and mistakes and also to reduce to a minimum the necessary changes of name when
the subdivisions of species are raised to specific rank or vice versa.

Article 30. Forms and half-breeds among cultivated plants should receive
fancy names, in common language, as different as possible from the Latin names of
the species or varieties. When they can be traced back to a species, a subspecies
or a botanical variety this is indicated by a succession of names.

Example: Pelargonium zonale Mrs. Pollock.

Subsection 5. Names of hybrids and half-breeds (mules)
This subsection contains four Articles and one Recommendation.
It is not included here as it deals with problems which are not met in
bacterial nomenclature.

Section 4- The publication of names and of the date of each name or com-

bination of names

Article 35. Publication is effected by the sale or public distribution of printed
matter or indelible autographs.

Communication of new names at a public meeting, or the placing of names in
collections or gardens open to the public, do not constitute publication.

Examples: Effective publication without printed matter: Salvia oxyodon
Webb and Heldr. was published in July, 1850, in an autograph catalogue and put
on sale (Webb and Heldreich, Catalogus plantarum hispanicarum, etc., ah. A.
Blanco lectarum, Parisiis, Jul., 1850, in folio). — Non-effective publication at a
public meeting: Cusson announced his establishment of the genus Physospermum
in a memoir read at the Society des Sciences des Montpellier in 1773, and later in
1782 or 1783 at the Soci6t6 de M^decine de Paris, but its effective publication
dates from 1787, in the M^moires de la Soc. Roy. de M^decine de Paris, vol. V,
1" partie.

Comment. The statement that the communication of new names at
a public meeting does not constitute valid publication, is of particular
interest to bacteriologists. Priority is always determined from date
of publication and not from date of presentation. A committee
appointed by the Society of American Bacteriologists on the classifica-
tion of bacteria at a meeting of the society recommended the use of
the generic name Erwinia to include certain bacteria producing
diseases of plants. This did not constitute valid publication.

130 GENERAL SYSTEMATIC BACTERIOLOGY

Article 36. On and after January 1, 1908, the publication of names of new
groups of living plants will be valid only when they are accompanied by a Latin
diagnosis. On and after January 1, 1912, the names of new groups of fossil plants
will not be considered valid unless accompanied by a Latin diagnosis and by
illustrations or figures showing the essential characteristics.

Comment. Bacteriologists in general have never subscribed to this
rule. It is unusual to find modern bacteriologists giving Latin descrip-
tion to new species, in fact the rule may be said to be quite commonly-
ignored by botanists. The committee on classification of the Society
of American Bacteriologists has recommended that bacteriologists
follow the International Botanical Code in the nomenclature of bacteria
with the exception of article 36.

Article 37. A species or a subdivision of a species, announced in a work, with
a complete specific or varietal name, but without diagnosis or reference to a
former description under another name, is not valid. Citation in synonymy or
incidental mention of a name is not effective publication, and the same applies
to the mention of name on a ticket issued with a dried plant without printed or
autographed diagnosis.

Plates accompanied with analyses are equivalent to a description; but this
applies only to plates published before January 1, 1908.

Article 38. A genus or any other group of higher rank than a species, named or
announced without being characterized conformably to article 37 cannot be
regarded as effectively published (nomen nudum). The mere indication of species
as belonging to a new genus or of genera as belonging to a higher group, does not
allow us to accept the genus or group in question as characterized and effectively
published. An exception is made in the case of the generic names mentioned by
Linnaeus in the Species Plantarum ed. 1., 1753, names which we associate with the
descriptions in the Genera Plantarum ed. 5., 1754 (see article 19).

Article 39. The date of a name or of a combination of names is that of their
effective publication. In the absence of proof to the contrary, the date placed
on the work containing the name or combination of names is regarded as correct.
On and after January 1, 1908, the date of publication of the Latin diagnosis only
can be taken into account in questions of priority.

Recommendations. Botanists will do well, in publishing, to conform to the
following recommendations :

XVIII. Not to publish a name without clearly indicating whether it is the name
of a family or a tribe, a genus or a section, a species or a variety; briefly, without
expressing an opinion on the nature of the group to which they give the name.

When names of new groups are published the author should designate the sub-
division which he considers as the type for the nomenclature of the group; he
should indicate the generic type in a family, the species type in a genus, the sub-
species or variety type in a species. This precaution will prevent difficulties in
nomenclature if it should become necessary later to dissociate such groups.

GENERAL SYSTEMATIC BACTERIOLOGY 131

Comment. The Zoological Code not only recommends that specific
types for genera and subgenera should be designated, but requires that
the names of families and orders should be derived from the names of
the type genera and type families respectively. This rule would be of
assistance in botany and in bacteriology.

Recommendation. XIX. To avoid publishing or mentioning in their publica-
tions unpublished names which they do not accept, especially if the person respon-
sible for these names have not formallj^ authorized their publication (see Rec.
XIV, e).

Recommendation. XX. When publishing new names in works written in a
modern language (floras, catalogues, etc.) to publish simultaneously the Latin
diagnoses and in paleobotany the figures which will make the names valid from
the point of view of scientific nomenclature.

In view of the particular difficulties indicated in the identification of fossil
plants, in addition to the Latin diagnosis, there should be included a detailed
description in French, German or Italian.

When new groups of the lower Cryptogames especially the fungi or other micro-
scopic plants are described, the description should be accompanied with a figure or
figures of these plants with the microscopic details which will aid in their
identification.

The description of a parasitic plant should always be followed by a designation
of the host, particularly in the parasitic fungi. The hosts should be designated
by their scientific Latin names and not by vernacular names in a modern language
for these frequently have more than one meaning.

Recommendation. XXI. To give the etymology of new generic names and also
of specific names when the meaning of the latter is not obvious.

XXII. To indicate precisely the date of publication of their works and that of
the placing on sale or the distribution of named and numbered plants when these
are accompanied by printed diagnoses. In the case of a work appearing in parts,
the last published sheet of a volume should indicate the precise dates at which
the different fascicles or parts of the volume were published, as well as the number
of pages in each.

XXIII. When works are published in periodicals to require the editor to indi-
cate on the separate copies the date (year and month) of publication and also the
title of the periodical from which the work is extracted.

XXIV. Separate copies should always bear the pagination of the periodical
of which they form a part, if desired they may also bear a separate pagination.

Section 5. On the 'precision to he given to names by the citation of the
author who first published them

Article 40. For the indication of the name or names of a group to be accurate
and complete, and in order that the date may be readily verified, it is necessary
to quote the author who first published the name or combination of names in
question.

Examples: Simarubaceae Lindley, Simaruba Aublet, Simaruba laevis Grise-
bach, Simaruba amara Aublet var. opaca Engler.

132 GENERAL SYSTEMATIC BACTERIOLOGY

Comment. It is evident from the reading of this rule that the author
of the name is frequently not the individual who first described the
organism. The name of the author is not quoted following the species
in order to designate the discoverer of the organism, or even one neces-
sarily who has studied it in detail, but merely to show who first used the
particular combination of letters or words constituting the name under
consideration. Any other procedure would be making the discoverer
of an organism responsible for a name with which he has never had
anything to do. As stated by Stiles (1905, p. 21) "This point of view
lays stress upon holding an author responsible for the names he pub-
lishes, rather than upon 'giving him credit' for these names. The
chief idea we have in citing the author of a name is to aid in tracing it."
For example, one of the cocci associated with pus production was first
adequately studied by Rosenbach and named by him Staphylococcus
alhus. Later it was renamed Albococcus albus by Winslow and Rogers.
Certainly Rosenbach is no way responsible for the latter generic name.
Welch discovered an organism which produced edema in man. He did
not give it a name. Later the organism was termed Bacillus Welchii.
We certainly could not write Bacillus Welchii Welch without giving the
impression that Welch had named an organism after himself.

Article 41. An alteration of the constituent characters or of the circumscrip-
tion of a group does not warrant the quotation of another author than the one who
first published the name or combination of names.

When the changes have been considerable, the words: mutatis charact., or pro
parte, or excl. gen., excl. sp., excl. var., or some other abridged indication, are
added after the citation of the original author, according to the nature of the
changes that have been made, and of the group in question.

Examples: Phyllanthus L. em. (emendavit) Miill. Arg. ; MyosotisL. pro parte,
R. Br.; Globularia cordifolia L. excl. var., etc.

Comment. The generic name Bacterium was first used by Ehren-
berg in 1828. His definition was somewhat modified by Dujardin in
1841. It was again modified by Cohn in 1872 and by Migula in 1894.
The name should always be written therefore. Bacterium Ehrenberg.
This does not indicate that we accept Ehrenberg's diagnosis of the
genus but merely that he first used this particular designation.

Article 42. When a manuscript name has been published and referred to its
author, the name of the person who published it should be appended to the cita-
tion. The same rule should be followed for names of garden origin when they
are cited as "Hort."

Article 43. When, in a genus, a name is applied to a group which is moved into
another group where it retains the same rank, or to a group which becomes of

GENERAL SYSTEMATIC BACTERIOLOGY 133

higher or lower rank than before, the change is equivalent to the creation of a new
group and the author who has affected the change is the one to be quoted. The
original author can be cited only in parenthesis.

Examples : Cheiranthus tristis L. when moved into the genus Matthiola becomes
Matthiola tristis R. Br., or Matthiola tristis (L.) R. Br. — Medicago polymorpha L.
var. orbicularis L. when raised to the rank of a species becomes Medicago orbicu-
laris Ail. or Medicago orbicularis (L.) All.

Comment. The corresponding zoological rule requires that the origi-
nal author shall be cited in parenthesis instead of leaving it optional as
in the above article.

Recommendation. XXV. Author's names put after names of plants are abbre-
viated, unless they are very short.

Section 6. On names that are to be retained when a group is divided,
remodelled, transferred, or moved from one rank to another, or when two
groups of the same rani: are united, or when they concern groups possess-
ing a pleomorphic cycle

Article 44. A change of characters, or a revision which involves the exclusion
of certain elements of a group or the addition of new elements, does not warrant
a change in the name or names of a group, except in cases provided for in article 51.

Examples : The genus Myosotis as revised by R. Brown differs from the original
genus of Linnaeus, but the name has not been changed, nor is any change allow-
able. Various authors have united with Centaurea Jacea L. one or two species
which Linnaeus had kept distinct; the group thus constituted must be called
Centaurea Jacea L. (sensu ampl.) or Centaurea Jacea L. (em. Visiani, em. Godron,
etc.) ; the creation of a new name such as Centaurea vulgaris Godr. is superfluous.

Article 45. When a genus is divided into two or more genera, the name must
be kept and given to one of the principal divisions. If the genus contains a section
or some other division which, judging by its name or its species, is the type or the
origin of the group, the name is reserved for that part of it. If there is no such
section or subdivision, but one of the parts detached contains a great many more
species than the others, the name is reserved for that part of it.

Examples: The genus Helianthemum contained, according to Dunal (in DC.
Prodr. I. 266-284), 412 well-known species distributed in nine sections; several
of these sections have since been raised to generic rank (Fumana Spach, Tuber-
aria Spach) but the name Helianthemum has been kept for the divisions
grouped round the section Euhelianthemum. The genus Convolvulus L. em.
Jacq. was divided into two by Robert Brown in 1810 {Prodr. fl. Nov. Holl.,
p. 482-484), who gave the name Calystegia to one of the genera which at the
time contained only four species, and reserved the name Cojivolvulus for the
other genus which contained a much larger number of species. In the same
way Salisbury (in Trans. Linn. Soc. VI, 317, 1802) in separating Erica vul-
garis L. from the genus Erica, under the name Calluna, kept the name Erica
for the large number of species left.

134 GENERAL SYSTEMATIC BACTERIOLOGY

Comrnent. Winslow and Rogers in 1905 divided the genus Staphy-
lococcus of Rosenbach into two genera Aurococcus and Albococcus, the
name Staphylococcus should have been retained for one of these groups.

Article 46. When two or more groups of the same nature are united, the
name of the oldest is retained. If the names are of the same date, the author
chooses and his choice cannot be modified by subsequent authors.

Examples: Hooker f. and Thomson (Fl. Ind. p. 67, 1855) united the genera
Wormia Rottb. and Capellia Bl. ; they gave the name Wormia to the genus thus
formed because the last name dates from 1783 while Capellia dates from 1825 —
In case of union of the two genera Cardamine and Deniaria, which were founded
at the same time by Linnaeus {Sp. PI. ed. 1, p. 653 and 654, 1753; Gen. PL ed.
5, n. 726, 727) the collective genus must be called Cardamine because that name
was chosen by Crantz {Class. Crucif., p. 126, 1769), who was the first to sug-
gest the union.

Recommendations. XXVI. Authors who have to choose between two
generic names should note the following recommendations:

1. Of two names of the same date to prefer the one which was first accom-
panied by the description of a species.

2. Of two names of the same date, both accompanied by descriptions of species,
to prefer the one, which, when the author made his choice, included the larger
number of species.

3. In cases of equality from these various points of view to prefer the more
correct and appropriate name.

XXVII. When several genera are united as subgenera or sections under one
generic name, that subdivision which was first distinguished or described may
retain its name (ex. Saxifraga aspera subsp. aspera) or bear a prefix (Alchemilla
alpina subsp. eualpina) or be designated by some customary title (normalis,
genuinus, typicus, originai'ius , verus, veridicus etc.). These prefixes or terms
lapse when the subdivisions are raised to specific rank.

Article 47. When a species or subdivision of a species is divided into two or
more groups of the same nature, if one of the two forms was distinguished or de-
scribed earlier than the other, the name is retained for that form.

Article 48. When a subgenus or section or species is moved into another
genus, when a variety or other division of a species is moved into another species,
retaining there the same rank, the original name of the subgenus or section, the
first specific epithet, or the original name of the division of the species must be
retained or must be reestablished, unless, in the new position there exists one of
the obstacles indicated in the articles of section 7.

Article 49. When a tribe becomes a family, a subgenus or a section becomes a
genus, a subdivision of a species becomes a species, or the reverse of these
changes takes place, and speaking generally when a group changes its rank,
the earliest name (or combination of names) received by the group in its new
position must be regarded as valid, if it is in conformity with the rules, unless
there exist any of the obstacles indicated in the articles of section 7.

Article 49a. Fungi having a pleomorphic evolutionary cycle in different suc-
cessive states of the same species carry only a single generic and specific name
(bin6me); the oldest which has been given beginning with Persoon (Synopsis)

GENERAL SYSTEMATIC BACTERIOLOGY 135

or Fries (Systema), to the state containing the form which is generally regarded
as being perfect, on condition that in other respects it conforms to the rules.

The ascus stage is considered the perfect state in the Ascomycetes, the basidia
as the stage in the Basidiomycetes, the teleutospore or its equivalent in the
Uredinales, and the spore in the Ustilaginales.

Generic and specific names given to other stages possess only a temporary value .
They are not to be used to replace a generic name already existing and applied to
one or more species, any one of which contains the form termed perfect.

The nomenclature of fungi with an evolutionary cycle, but not pleomorphic
follows the ordinary rules of nomenclature.

Recommendations. XXIX. 1°. When a sub-tribe becomes a tribe, when a
tribe becomes a subfamily, when a subfamily becomes a family, etc., or when the
inverse changes occur, do not alter the root of a name but only the termination
(-inae, -eae, -oideae, -ineae, -ales, etc.), unless in the new position, one of the
obstacles indicated in the articles of section 7, supervenes, or the new designation
becomes a source of error, or there is some other serious reason against it.

2°. When a section or a subgenus becomes a genus, or the inverse changes take
place, retain the old names, unless this results in two genera of plants having the
same name, or the existence of two subdivisions of the same name in the same
genus, or one of the obstacles indicated in the articles of section 7 supervenes.

3°. When a subdivision of a species becomes a species or the inverse change
occurs, retain the original epithets, unless this results in two species bearing the
same name in the same genus, or two subdivisions bearing the same name in the
same species, or unless any of the obstacles indicated in section 7 supervenes.

Section 7. On names that are to he rejected, changed or modified

Article 50. No one is authorized to reject, change or modify a name (or com-
bination of names) because it is badly chosen, or disagreeable, or another is pref-
erable or better known, or because of the existence of an earlier homonym which
is universally regarded as non-valid, or for any other motive either contestable or
of little import. (See also art. 57.)

Recommendations. See on the subject of homonyms recommendations Vb
and XIV which suggest that cases of this kind should be avoided for the future.

Comment. A large proportion of the names which have been suggested
for genera and species of bacteria must be rejected because of violation
of this article. Orla-Jensen (1909) for example, created a large number
of new genera, in order to make them conform to his ideas of fitness.
Where such names are applied to groups which have had no previous
generic designation they are, of course, valid, but he was not justified
in substituting names which he preferred for old and valid designations.

The expression "because of the existence of an earlier homonym which
is universally regarded as non-valid" is one which permits of a variety
of interpretations. The zoologists insist upon the rejection of any name
which is a homonym of an earlier term. In this respect the two codes
are at variance.

136 GENERAL SYSTEMATIC BACTERIOLOGY

Article 51. Every one should refuse to admit a name in the following cases:

1. When the name is applied in the plant kingdom to a group which has an
earlier valid name.

2. When it duplicates the name of a class, order, family or genus, or a sub-
division or species of the same genus, or a subdivision of the same species.

3. When it is based on a monstrosity.

4. When the group which it designates embraces elements altogether incoher-
ent, or when it becomes a permanent source of confusion or error.

5. When it is contrary to the rules of sections 4 and 6.

Comments. 1. The generic name Pneumococcus of Schmidlechner
(1905) is an invalid synonym because of the older name Diplococcus
given to the same group by Weichselbaum (1886).

2. The generic name Myxococcus of Gonnermann (1907) duplicates
the name of an entirely different group termed Myxococcus by Thaxter
(1892).

4. Much difficulty is found in bacteriology in determining the proper
designation for some of the older species of bacteria because of the fact
that some of the older authors were dealing with mixed or impure
cultures.

Article 53. When a subgenus, a section or a subsection, passes as such into
another genus, the name must be changed if there is already in that genus a valid
group of the same rank, under the same name.

When a species is moved from one genus into another, its specific epithet must
be changed if it is already borne by a valid species of the genus. Similarly when
a subspecies, a variety, or some other subdivision of a species is placed under
another species, its name must be changed if borne already by a valid form of
like rank in that species.

Article 54. Names of genera must be rejected in the following special cases:

1. When they coincide with technical term currently employed in morphology
unless they are accompanied by specific names.

2. When they express uninomial nomenclature.

4. When they are formed of two words, unless these two words were from the
first united or joined by a hyphen.

Examples: 1°. Generic names such as Ligmim, Radix, Spina, etc., would not
now be admissible, on the other hand a generic name like Tuber should not be
rejected when it has been published with specific names {Tuber cibarium, etc.). —
2° Ehrhart {Phytophylacium (1780)) and Beiirage (IV, 145-150) made use of a
uninomial nomenclature for species known at that time under binary names
{Phaeocephalum, Leptostachys, etc.). These names, which resemble generic
names, must not be confused with such and are to be rejected, unless a subse-
quent author has given them the value of a generic name : for example Baeothryon,
a uninomial expression of Ehrhart's has been applied to a genus characterized by
A. Dietrich Spec. PI. II, 89 (1833). — Names like Quisqualis (a single word from
the first), Sebastiano-Schaueria and Neves-Armondia will stand.

GENERAL SYSTEMATIC BACTERIOLOGY 137

Article 55. Specific names must also be rejected in the following special
cases :

1°. When they are ordinals serving for purpose of enumeration.

2°. When they merely repeat the generic name.

Examples: 1°. Boletus vicesimus sextus, Agaricus octogesimus nonit^. 2 .
Linaria Linaria, Raphanistrum Raphanisirum, etc.

Comments. 1. Many bacterial species have been named by the use
of numbers or letters. Where these can be clearly differentiated, new
specific names must be given.

2. This iTjle in the botanical code is contrary to that in the Zoologi-
cal Code. Names such as Apis apis maybe used in zoological literature,
but not in botanj^ hence not in bacteriology. A varietal name may be
the same as its species but the species name must be different from its
genus. In zoology on the other hand, variety, genus and species may
all have the same name.

Article 56. In the cases foreseen in articles 51 to .56, the name to be rejected
or changed is replaced by the oldest valid name in the group in question, and in
default of such a one a new name (a new binomial) must be made.

By a valid name is meant a name or more particularly a combination of names
created in conformity with the whole of the rules of nomenclature. The author
of a new combination ought to borrow the specific epithet of an old non-valid
binomial, or employ a new name.

Article 57. The original spelling of a name must be retained, except in case
of a typographic or orthographic error. When the difference between two names,
especially two generic names, lies in the termination, these names are to be
regarded as distinct even though differing by one letter only.

Examples: Rubia and Rubus, Monochaete and Monochaetum, Peponia and
Peponium, Iria and Iris.

Recommendations. XXX. The liberty of making orthographic corrections
must be used with reserve, especially if the change effects the first syllable, and
above all the first letter of a name.

XXXI. Many names differ by a single letter without risk of confusion (ex.
Durmllea and Urvillea). In cases where a close approach to identity is a source
of error (ex. Astrostemma and Asterostemma in one and the same family, Asclepi-
adaceae, Pleuripetalum and Pleuropetalum in Orchidaceae) only one, the older, of
the names should be kept, in accordance with article 51, 4 .

Chapter IV. Modification of the rules of botanical nomenclature

Article 58. The rules of botanical nomenclature can only be modified by com-
petent persons at an International Congress convened for the express purpose.

C. THE INTERNATIONAL RULES OF ZOOLOGICAL NOMENCLATURE

Although the bacteria are plants, and the bacteriologist is for the
most part dealing with bacteria, it must be recognized that the bacteria

138 GENERAL SYSTEMATIC BACTERIOLOGY

intergrade with the protozoa. The bacteriologist must frequently-
deal also with problems in the nomenclature of protozoa, or even of
higher animals. He is therefore vitally interested in the rules used by
the zoologist in his systematic nomenclature.

In many respects the zoological rules are more explicit than those of
the botanist. They constitute primarily a type basis code. To many
bacteriologists this appears to be highly desirable in the field of bac-
teriology. While the Zoological Code therefore cannot govern bacterial
nomenclature, nevertheless an understanding of its rules and recommen-
dations would be of great value in determining good usage on points
not covered in the Botanical Code.

The code given below is that adopted by the Ninth International
Zoological Congress at Monaco, 1913.

Article 1. Zoological nomenclature is independent of botanical nomenclature
in the sense that the name of an animal is not to be rejected simply because it is
identical with the name of a plant. If, however, an organism is transferred from
the vegetable to the animal kingdom its botanical names are to be accepted in
zoological nomenclature with their original botanical status; and if an organism
is transferred from the animal to the vegetable kingdom its names retain their
zoological status.

Recommendation. It is well to avoid introducing into zoology as generic names
such names as are in use in botany.

Article 2. The scientific designation of animals is uninominal for subgenera
and all higher groups, binominal for species, and trinominal for subspecies.

Article 3. The scientific names of animals must be words which are either Latin
or Latinized, or considered and treated as such in case they are not of
classic origin.

Family and subfamily names

Article 4. The name of a family is formed by adding the ending idae, the name
of a subfamily by adding inae to the stem of the name of its type genus.

Article 5. The name of a family or subfamily is to be changed when its type
genus is changed.

Generic and subgeneric names

Article 6. Generic and subgeneric names are subject to the same rules and
recommendations, and from a nomenclatural standpoint they are coordinate, that
is, they are of the same value.

Article 7. A generic name becomes a subgeneric name, when the genus so
named becomes a subgenus, and vice versa.

Article 8. A generic name must consist of a single word, simple or compound,
written with an initial capital letter, and employed as a substantive in the nomi-
native singular. Examples: Cenis, Porca, Ceratodus, Hymenolepis.

GENERAL SYSTEMATIC BACTERIOLOGY 139

Recommendation. Certain biological groups which have been proposed dis-
tinctly as collective groups, not as systematic units, may be treated for conveni-
ence as if they were genera, but they require no type species. Examples: Aga-
modistoimmi, Amphistomulum, Agarnofilaria, Agamomermis, Sparc/anum.

Recommendations. The following words may be taken as generic names.

a. Greek substantives, for which the rules of Latin transcription (translitera-
tion (see Appendix F)) should be followed. Examples: Ancylus, Amphibola,
Aplysia, Pompholyx, Physa, Cylichna.

b. Compound Greek words, in which the attributive should precede the
principal word. Examples: Stenogyra, Pleurobrachus, Tylodina, Cyclostomum,
Sarcocystis, Pelodytes, Hydrophilus, Rhizobius.

This does not, however, exclude words formed on the model of Hippopotamus,
namely, words in which the attributive follows the principal word. Examples:
Philydrus, Biorhiza.

c. Latin substantives. Examples: Ancilla, Auricula, Dolium, Harpa, Oliva.
Adjectives (Prasina), past participles (Productv^) are not recommended.

d. Compound Latin words. Examples: Stiliger, Dolabrifer, Semifusus.

e. Greek or Latin derivatives expressing diminution, comparison, resemblance,
or possession. Examples: Dolium, Doliolum; Strong ylus, Eustrongylus; Limax,
Limacella, Limacia, Limacina, Limacites, Limacula, Lingula, Lingullella,
Lingulepis, Lingulina, Lingulops, Lingulopsis; Neomenia, Proneomenia; Buteo,
Archibuteo; Gordius, Paragordius, Polygordius.

f. Mythological or heroic names. Examples: Osiris, Venus, Brisinga, Vel-
leda, Crimora. If not Latin, these should be given a Latin termination {Aegiru,s,
Gondulia).

g. Proper names used by the ancients. Examples: Cleopatra, Belisarius,
Melania.

h. Modern patronymics, to which is added an ending to denote dedication.

a. Names terminating with a consonant taking the ending ius, ia, or ium.
Examples: Stelysius, Lamarckia, Kollikeria, Mulleria, Stalia, Kryeria, Ibanezia.

j8. Names terminating with the vowels e, i, o, u, or y take the ending us, a or
um. Examples: Blainvillea, Wyvillea, Cavolina, Fatioa, Bernaya, Quoya,
Schulzea.

y. Names terminating with a take the ending ia. Example: Danaia.

S. In generic names formed from patronymics, the particles are omitted if not
coalesced with the name, but the articles are retained. Examples: Blainvillea,
Benedenia, Chiajea, Lacepedea, Dumerilia.

€. With patronj'mics consisting of two words, only one of these is used in the
formation of a generic name. Examples: Selysius, Targionia, Edwardsia,
Duthiersia.

f . The use of proper names in the formation of compound generic names is ob-
jectionable. Examples: Eugrimmia, Buchiceras, Heromorpha, Mobiusispongia.

i. Names of ships which should be treated the same as mythological
names (Vega) or as modern patronymics. Examples: Blakea, Hirondellea,
Challengeria.

j. Barbarous names, that is, words of nonclassic origin. Examples : Vanikoro,
Chilosa. Such words may receive a Latin termination. Examples: Yetus^
Fossarus.

140 GENERAL SYSTEMATIC BACTERIOLOGY

k. Words formed by an arbitrary combination of letters. Examples: Neda,
Clanculus, Salifa, Torix.

1. Names formed by anagram. Examples: Dacelo, Verlusia f Linospa.

Article 9. If a genus is divided into subgenera, the name of the typical sub-
genus must be the same as the name of the genus (see Art. 25).

Article 10. When it is desired to cite the name of a subgenus, this name is to
be placed in parentheses between the generic and the specific names. Examples:
Vanessa (Pyrameis) cardui.

Specific and subspecific names

Article 11. Specific and subspecific names are subject to the same rules and
recommendations, and from a nomenclatura.1 standpoint they are coordinate,
that is, they are of the same value.

Article 12. A specific name becomes a subspecific name when the species so
named becomes a subspecies, and vice versa.

Article 13. While specific substantive names derived from names of persons
may be written with a capital initial letter, all other specific names are to be
written with a small initial letter. Examples: Rhizostoma Cuvieri or Rh. cuvi-
eri, Francolinus Lucani, or F. lucani, Hypoderma Diana or H. diana, Laophonte
Mohammed or L. mohammed, Oestrus ovis, Corvus corax.

Article 14. Specific names are:

a. Adjectives, which must agree grammatically with the generic name.
Example: Felis viarmorala.

b. Substantives in the nominative in apposition with the generic name. Ex-
ample: Felis leo.

c. Substantives in the genitive. Examples: Rosae, sturionis, antillarum,
galliae, sancti-pauli, sanctae-helenae.

If the name is given as a dedication to one or several persons, the genitive is
formed in accordance with the rules of Latin declination in case the name was
employed and declined in Latin. Examples: Plinii, Aristolelis, Vicloris,
Antonii, Elisabethae, Petri (given name).

If the name is a modern patronj^mic, the genitive is always formed by adding,
to the exact and complete name, an i if the person is a man, or an ae if the person
is a woman, even if the name has a Latin form; it is placed in the plural if the
dedication involves several persons of the same name. Examples: Cuviei,
Mobiusi, Nunezi, Merianae, Sarasinorum, Bovi (not Bovis), Salmoni (not
Salmonis).

Recoinmendation. The best specific name is a Latin adjective, short, euphonic,
and of easy pronunciation. Latinized Greek words or barbarous words may,
however, be used. Examples: gymnocephalus, echinococcus, ziczac, aguti, hoacili,
urubitinga.

It is well to avoid the introduction of the names typicus and typus as new names
for species or subspecies, since these names are always liable to result in later
confusion.

Article 15. The use of compound proper names indicating dedication, or of
compound words indicating a comparison with a simple object does not form an
exception to Article 2. In these cases the two words composing the specific name

GENERAL SYSTEMATIC BACTERIOLOGY 141

are written as one word with or without the hyphen. Examples: Sanctae-
Catharinae or sanctacatherinae, jan-mayeni, or janmayeni, cornu-pastoris or
cornupastoris, cor-anguinum or coranguinum, cedo-nuUi or cedonulli.

Expressions like rudis planusque are not admissible as specific names.

Article 16. Geographic names are to be given as substantives in the genitive,
or are to be placed in an adjectival form. Examples: sancti-pauli, sanctae-
helenae, edwardiensis, diemenensis , magellanicus, burdigalensis, vindobonensis .

Recommendation. Geographic names used by the Romans or by Latin writers
of the middle ages are to be adopted in preference to more recent forms. Words
like bordeausiacus and viennensis are poor, but are not to be rejected on this
account.

Article 17. If it is desired to cite the subspecific name, such name is written
immediately following the specific name, without the interposition of any mark
of punctuation. Example: Rana esculenta marmorata Hallowell, but not i?ana
esculenta {marmorata) or Rana marmorata Hallowell.

Article 18. The notation of hybrids may be given in several ways; in all cases
the name of the male parent precedes that of the female parent, with or with-
out the sexual signs :

a. The names of the two parents are united by the sign of multiplication (X).

b. Hybrids may also be cited in the form of a fraction, the male parent forming

Capra hircus

the numerator and the female parent the denominator. Example: — ——. : — '

Oils aries

This second method is in so far preferable that it permits the citation of the person

who first published the hybrid form as such. Example:

Bernicla canadensis _ ,

— — Rabe.

Anser cygnotdes

c. The fractional form is also preferable in case one of the parents is itself a

, , . , .^ , Tetrao tetrix X Tetrao urogallus ^ , , .

hybrid. Example: — . In the latter case, how-

Gallus gallus

ever, the parentheses may be used. Example: {Tetrao tetrix X, Tetrao urogallus)

X Gallus gallus.

d. When the parents of the hybrid are not known as such (parents), the hybrid
takes provisionally a specific name, the same as if it were a true species, namely,
as if it were not a hybrid; but the generic name is preceded by the sign of multi-
plication. Example : X Coregonus dolosv^ Fatio.

Formation, derivation, and orthography of zoological names

Article 19. The original orthography^ of a name is to be preserved unless an
error of transcription, a lapsus calami, or a typographical error is evident.

Recommendation. For scientific names it is advisable to use some other
type than that used for the text. Example: Rana esculenta (italics) Linne,
1758, lives in Europe.

Article 20. In forming names derived from languages in which the Latin alpha-
bet is used, the exact original spelling, including diacritic marks, is to be retained.
Examples: Selysiv^, Lamarckia, Kollikeria, Miilleria, Stalia, Krpyeria, Ibanezia,
Mobiusi, Medici, Czjzeki, spitzbergensis, islandicus, paraguayensis, patagonicus,
barbadensis, faroensis.

142 GENERAL SYSTEMATIC BACTERIOLOGY

Recommendations. The prefixes sub and pseudo should be used only with ad-
jectives and substantives, sub with Latin words, pseudo with Greek words, and
they should not be used in combination with proper names. Examples: sub-
viridis, subchelatus, Pseudacanthus, Pseudophis, Pseudomys. Words like sub-
wilsoni and pseudo-grateloupana are not recommended.

The terminations oides and ides should be used in combination only with Greek
or Latin substantives ; they should not be used in combination with proper names.

Geographic and patronymic names from countries which have no recognized
orthography or which do not use the Latin alphabet, should be transcribed into
Latin according to the rules adopted by the Geographic Society of Paris. (See
Appendix G.)

In proposing new names based upon personal names, which are written some-
times with a, 6 or ii, at other times with ae, oe, and ue, it is recommended that
authors adopt ae, oe and ue. Example muelleri in preference to miilleri.

Author's name.

Article 21. The author of a scientific name is that person who first publishes
the name in connection with an indication, a definition, or a description, unless
it is clear from the contents of the publication that some other person is respon-
sible for said name and its indication, definition, or description.

Article 22. If it is desired to cite the author's name, this should follow the
scientific name without interposition of any mark of punctuation; if other cita-
tions are desirable (date, sp. n., emend., sensu stricto, etc.) these follow after the
author's name, but are separated from it by a comma or by parenthesis. Exam-
ples: Primates Linn6, 1758, or Primates Linne (1758).

Recommendation. When the name of the author of a scientific name is abbre-
viated, the writer will do well to conform to the list of abbreviations published
by the Zoological Museum of Berlin.

Article 23. When a species is transferred to another than the original genus
or the specific name is combined with any other generic name than that with which
it was originally published, the name of the author of the specific name is retained
in the notation but placed in parentheses. Examples: Taenia lata Linn6, 1758,
and Dibothriocephalus latus (Linne, 1758); Fasciola hepatica Linn6, 1758, and
Distoma hepaticum (Linn6, 1758).

If it is desired to cite the author of the new combination his name follows the
parentheses. Example: Limnatis niloiica (Savigny, 1820) Moquin-Tandon, 1826.

Article 24. When a species is divided, the restricted species to which the
original specific name of the primitive species is attributed may receive a notation
indicating both the name of the original author and the name of the reviser.
Example: Taenia solium Linn6, partim, Goeze.

The law of priority

Article 25. The valid name of a genus or species can be only that name under
which it was first designated on the condition :

a. That this name was published and accompanied by an indication, or a
definition, or a description; and

b. That the author has applied the principles of binary nomenclature.

GENERAL SYSTEMATIC BACTERIOLOGY 143

Application of the law of priority

Article 26. The Law of Priority obtains and consequently the oldest available
name is retained:

a. When any part of an animal is named before the animal itself.

b. When any stage in the life history is named before the adult.

c. When the two sexes of an animal have been considered as distinct species
or even as belonging to distinct genera.

d. When an animal represents a regular succession of dissimilar generations
which have been considered as belonging to different species or even to different
genera.

Article 28. A genus formed by the union of two or more genera or subgenera
takes the oldest valid generic or subgeneric name of its components. If the
names are of the same date, that selected by the first reviser shall stand.

The same rule obtains when two or more species or subspecies are united to
form a single species or subspecies.

Recommendation. In absence of anj'- previous revision, the establishment of
precedence by the following method is recommended:

a. A generic name accompanied by specification of a type has precedence over
a name without such specifications. If all or none of the genera have types
specified, that generic name takes precedence the diagnosis of which is most
pertinent.

b. A specific name accompanied by both description and figure stands in prefer-
ence to one accompanied only by a diagnosis or only by a figure.

c. Other things being equal, that name is to be preferred which stands first
in the publication (page precedence).

Article 29. If a genus is divided into two or more restricted genera, its valid
name must be retained for one of the restricted genera. If a type was originally
established for said genus, the generic name is retained for the restricted genus
containing said type.

Recommendation. To facilitate reference, it is recommended that when an
older species is taken as type of a new genus, its name should be actually com-
bined with the new generic name in addition to citing it with the old generic
name. Example: Gilbertella Eigenmann, 1903, Smithsonian Misc. Coll. v. 45,
p. 147, type Gilbertella alata (Steindachner) = Anacyrtus alatits Steindachner.

Article 30. The designation of type species of genera shall be governed by the
following rules (a-g), applied in the following order of precedence:

I. Cases in which the generic type is accepted solely upon the basis of the
original publications:

a. When in the original publication of a genus, one of the species is definitely
designated as tj^je, this species shall be accepted as type, regardless of any other
considerations. (Type by original designation.)

b. If in the original publication of a genus, typicus or typus is used as a new
specific name for one of the species, such use shall be construed as "tj^ie by
original designation."

c. A genus proposed with a single original species takes that species as its type.
(Monotypical genera.)

d. If a genus, without originally designated (see a) or indicated (see b) type,
contains among its original species one possessing the generic name as its specific

144 GENERAL SYSTEMATIC BACTERIOLOGY

or siibspeoiiic njuuo. oithor as valid iiamo or synonym, that species or subspecies
beci>nies i^K^o facto type of the genus. (IVpe by nbsolute tautonymy.)

II. Cases in which the generic type is accepted not solely upon basis of the
original publicat ion :

e. The following species are excluded front consideration in ileterniining the
types of genera.

a. Species which were not included vuvder the generic name at the time of its
original publication.

/S. Species which were special ituiuirendae from the standpoint of the author
of the generic name at the time of its publication.

-). Species which the author of the genus doubtfully referred to it.

f. In case a generic name without origitially designated type is proposed as a
substitute for another generic name, with or without type, the type of either,
when established, becomes ii\<o fado type of other.

g. If an author, in publishing a genus with more than one valid species, fails to
designate (.see a^ or to indicate (.see b, d"* its type, any subsequent author may
select the type, and such designation is not subject to change. (.Type by subse-
quent ilesignatioit."*

The meaning of the expression ''select the type" is to be rigidly construed.
Mention of a species as an illustration or example of a genus does not constitute
a selection of a type.

III. Recommendations. In selecting types by subsequent designation, authors
will do well to govern themselves by the following recommendations:

h. In case of Linnaean genera, select as type the most common or the medicinal
species. (^Liunaean rule, 1751. )

1. If a genus, without designated type, contains among its original species one
possessing as a specific or subspocitic name, either as valid name or synonyni, a
name which is virtually the same as the generic nan\e. or of the same origin or
same meaning, preference should be shown to that species in designating the type,
unless such prefertMice is strongly contraindicated by other factors. (.Tjpe by
virtual tautonymy.) Examples: Bos taurus, Equus caballus. Oris aries. Scomber
scombri!^, Sphaerostoma glohiporum; contraindicated in Dipetalonen.a (compare
species Filaria dipetata, of which only one sex was described, based upon one
specimen and not studieil in detaiP.

j. If the genus contains both exotic and nonexotie species from the standpoint
of the original author, the type should be selected from the nonexotie species.

k. If some of the original species have later been classitied in other genera,
preference should be shown to the species still remaining in the original genus.
(TyiH> by elimination.)

1. Species based upon sexually mature specimens should take precedence over
sjH^cies based upon larval or immature forms.

m. Show pivference to species bearing the name conimunis, vulgaris, rnedicina-
lis, or officinalis.

n. Show preference to the best described, best figured, best known, or most
easily obtainable species, or to one of which a type specimen can be obtained.

o. Show preference to a species which belongs to a group containing as large a
number of the species as possible. (.De Candolle's rule. )

p. In parasitic genera, select, if possible, a species which occurs in the man or
some food animal or in some very common and widespread host species.

GENERAL SYSTEMATIC BACTERIOLOGY 145

q. All other things being equal, show preference to a species which the author
of the genus actually studied at or before the time he proposed the genus.

r. In case of writers who habitually placed a certain leading or typical species
first as "chef de file," the others being described by comparative reference to this,
this fact should be considered in the choice of the type species.

s. In case of those authors who have adopted the "first species rule" in fi.xing
generic types, the first species named by them should be taken as types of their
genera.

t. All other things being equal, page precedence should obtain in selecting a
type.

Article 32. A generic or a specific name, once published, can not be rejected,
even by its author, because of inappropriateness. Examples: Names like Polyo-
don, Apus, albus, etc., when once published, are not to be rejected because of a
claim that they indicate characters contradictory to those possessed by the
animals in question.

Article 33. A name is not to be rejected because of tautonyray, that is, because
the specific or the specific and subspecific names are identical with the generic
name. Examples: Truiia irutla, Apufi apus apus.

Article 34. A generic name is to be rejected as a homonym when it has previ-
ously been used for some other genus of animals. Example : Trichina Owen, 1835,
nematode, is rejected as homonym (1) of Trichi7ia Meigen, 1830, insect.

Article 35. A specific name is to be rejected as a homonym (1) when it has
previously been used for some other species of the same genus. Examples:
Taenia ovilla Rivolta, 1878 (n. sp.) is rejected as homonym of T. ovilla Gmelin,
1790.

When in consequence of the union of two genera, two different animals having
the same specific or subspecific name are brought into one genus, the more recent
specific or subspecific name is to be rejected as a homonym.

Specific names of the same origin and meaning shall be considered homonyms
if they are distinguished from each other only by the following differences:

a. The use of ae, o?,, and e, as caeruleus, coeruleus, ceruleus; ei, i, and y, as
chiropus, cheiropus; c and k as microdon, mikrodon.

b. The aspiration or non-aspiration of a consonant, as oxyryncus, ocyrhynchus.

c. The presence or absence of a c before t, as autumnalis, aiLctumnalis .

d. By a single or double consonant; liloralis, littoralis.

e. By the endings ensis and iensis to a geographical name, as timorensis,
limoriensis.

Article 36. Rejected homonyms (1) can never be again used. Rejected
synonyms can again be used in case of the restoration of erroneously suppressed
groups. Example: Taenia (Jiardi Moniez, 1870, was suppressed as a synonym
of Taenia ovilla Rivolta, 1878; later it was discovered that Taenia ovilla was pre-
occupied {Taenia ovilla Gmelin, 1790). Taenia ovilla, 1878, is suppressed as a
homonym, and can never again be used; it was stillborn and cannot be brought to
life, even when the species is placed in another genus {Thysanosoma) . Taenia
Giardi, 1879, which was suppressed as a synonym, becomes valid upon the sup-
pression of the homonj'm Taenia ovilla Rivolta.

Recommendations. It is well to avoid the introduction of new generic names
which difTer from generic names already in use only in termination or in a slight

146 GENERAL SYSTEMATIC BACTERIOLOGY

variation in spelling which might lead to confusion. But when once introduced,
such names are not to be rejected on this account. Examples: Picus, Pica;
Polyodus, Polyodon, Polyodonta, Polyodontas, Polyodontus.

The same recommendation applies to new specific names in any given genus.
Examples : necator, necatrix; furcigera, furcifera; rhopalocephala, rhopaliocephala.

If from the radical of a geographic name two or more adjectives are derived,
it is not advisable to use more than one of them as specific name in the same
genus, but if once introduced they are not to be rejected on this account. Exam-
ples: hispanus, hispanicus; moluccanus molluccensis; sinensis, sinicus, chinensis;
ceylonicus, zeylanicus.

The same recommendation applies also to other words derived from the same
radical and differing from each other only in termination or by a simple change in
spelling.

D. TYPE BASIS CODE SUGGESTED BY A COMMITTEE ON BOTANICAL
NOMENCLATURE OF THE BOTANICAL SOCIETY OF AMERICA

For a number of years the botanists of America have been divided
into two groups, those who use the Vienna Code and those who use the
socalled "American Code." In 1918 a Committee on Botanical Nomen-
clature was appointed by the Botanical Society of America to consider
this subject and report. In 1920 the committee gave a majority report
signed by seven of its members and a minority report signed by two.
The majority report outlined a Type Basis Code of Botanical Nomen-
clature. The report is of so much importance that it is given below in
full.

The Committee on Nomenclature of the Botanical Society of America was
appointed at the Baltimore meeting of the Society in 1918. A preliminary survey
of the situation showed that the taxonomists of the Society were about equally
divided in their support of the Vienna Code and the American Code. An at-
tempt to commit the Society to one or the other of these codes would inevitably
result in conflict detrimental to progress in nomenclatural matters. The policy
was adopted of working on nomenclature along parallel lines. Two subcom-
mittees were appointed, one on the Vienna Code, with J. M. Greenman as chair-
man, and one on the American Code, with A. S. Hitchcock as chairman.

The subcommittee on the American Code has prepared a plan which is now
submitted to the Society. It is not asked that the Society commit itself to this
plan by adopting the report but it is hoped that the Society will receive the report
without prejudice. The committee will then continue to study the plan and
modify it if necessary to meet the wishes of its supporters. A part of the plan
is the establishment of a Nomenclature Commission to pass upon exceptions to
the Code. The Committee asks authority to organize this Commission.

We wish especially to call attention of the Society to the fact that the new code
which we call the Type-basis Code is not antagonistic to the Vienna Code but is
based upon the same principles with certain additions. Both codes are based
upon the principle of priority. Both admit exceptions to the application of the

GENERAL SYSTEMATIC BACTERIOLOGY 147

rules. The Type-basis Code provides for a Commission to pass upon exceptions.
The fundamental difference is the acceptance by the Type-basis Code of the prin-
ciple of Nomenclatural Types. This principle is not included in the Vienna Code
but is not antagonistic to it. The Committee offers the Type-basis Code of
Botanical Nomenclature as a new code international in its scope with the hope
that its merits will be so evident that it will receive support both in this country
and abroad and that it may be combined with the Vienna Code at the next inter-
national Congress. The chief differences between the two codes are (1) the con-
cept of types, and (2) the idea of a commission to validate exceptions.

A type-basis code of botanical nomenclature. Principles.

1. The primary object of formal nomenclature in systematic biology
is to secure stability, uniformity, and convenience in the designation
of plants and animals.

2. Botanical nomenclature is treated as beginning with the general
applications of binomial names to plants (Linnaeus' Species Plantarum,
1753).

3. Priority of publication is a fundamental principle of botanical
nomenclature. Two groups of the same category cannot bear the same
name.

Note a. This principle applies primarily to genera and species.
Note b. Previous use of a name in zoology does not preclude its
use in botany; but the proposal of such a name should be avoided.

4. The application of names is determined by means of nomencla-
tural types.

Note. A generic name is always so applied as to include its type
species; a specific name is always so applied as to include its type
specimen.

Rules and recommendations

Section 1 . Publication of names

Article 1. A specific name is published when it has been printed and distrib-
uted with a description, or with a reference to a previously published
description.

Note. A recognizable figure may be the equivalent of a description in the
literature of paleobotany and diatoms.

a. In the transfer of a species from one genus to another, the original specific
name is retained, unless the resulting binomial has been previously published.

Recommendations. Botanists will do well, in publishing:

1, In describing parasitic fungi to indicate the host and to designate the name
of the host by its scientific Latin name.

2. To give the etymology of all new generic names.

Article 2. A generic name is published when it has been printed and
distributed.

148 GENERAL SYSTEMATIC BACTERIOLOGY

a. With a generic or specific description (or a recognizable figure, see Article 1,
note) and a binomial specific name.

b. With a generic and specific name and the citation of a previously published
description.

c. With a definite reference to at least one previously published binomial.

Note a. A name is not published by its citation in synonymy, nor by inciden-
tal mention. Such a name may be taken up but not to replace one already prop-
erly published.

Note b. Of names published in the same work and at the same time, those
having precedence of position are to be regarded as having priority.

Recommendation. Botanists will do well, in publishing, to give the etymology
of specific names when their meaning is not obvious.

Section 2. Application of names

Article 3. The nomenclatural tj'pe of a species is the specimen or the most
important of the specimens upon which its original published description was
based.

a. If only one specimen is cited, that is the type.

b. If one specimen is designated as the type, that specimen shall be so accepted,
unless an error can be demonstrated.

c. A species transferred without change of name from one genus to another
retains the original type even though the description under the new genus was
drawn from a different species.

d. The publication of a new specific name as an avowed substitute for an earlier
one does not change the type of the species.

e. When more than one specimen was originally cited and no type was desig-
nated the type should be selected in the following manner:

1. The type specimen interprets the description and fixes the application of the
name, hence, primarilj' the description controls the selection of the type.

2. The type may be indicated by the specific name, this being sometimes
derived from the collector, locality, or host.

3. If one specimen is figured in connection with the original description this
may usually be regarded as the type.

4. Specimens that are mentioned by the author as being exceptional or unusual,
or those which definitely disagree with the description (provided others agree)
may usually be excluded from consideration in selecting the type.

5. An examination of the actual sheets of specimens studied by the author
may aid in determining or selecting the type. He may have written the name
or left notes or drawings upon one of the sheets.

Note. Specimens known to have been received by the author subsequent
to the study resulting in the original publication should be excluded from
consideration.

6. If an author, in publishing a new species, gives a description of his own, this
takes precedence over synonymy or cited descriptions, in determining the type
specimen.

Article 4, The nomenclatural type species of a genus is the species or one of
the species included when the genus was originally published.

GENERAL SYSTEMATIC BACTERIOLOGY 149

a. If a genus includes but one species when originally published this species
is the type.

b. When more than one species is included in the original publication of the
genus, the type is determined by the following rules (these rules are Articles 3
to 6 of the Report of the Committee on Generic Types published in (1) Science
N. S. 49: 334-33G. 1919, (2) Bot. Soc. Amer. Publ. 73, 70-71. 1919).

Recommendations. In the future it is recommended that authors of generic
names definitely designate type species; and that in the selection of tj^pes of gen-
era previously published, but of which the type would not be indicated by the
preceding rules, the following points be taken into consideration. (This includes
Article 7, a to g, of the Report on Generic Types published in Science and in
Bot. Soc. Amer. Publ. 73, loc. cit.)

Section 3. Rejection of Names

Article 5. A name is rejected

a. When preoccupied (homonym).

1. A specific name is a homonym when it has been published for another species
under the same generic name.

2. A generic name is a homonym when previously published for another genus.

3. Similar names are to be treated as homonyms only when they are mere varia-
tions in the spelling of the same word; or in the case of specific names, when they
differ only in adjective or genitive termination.

b. When there is an older valid name based on another member of the same
group (metonym).

c. When there is an older valid name based on the same type (typonym).

d. When it has not been effectively published according to the provisions of
Section 1 of these rules (hyponym).

Article 6. There may be exceptions to the application of the principles and
rules of this Code in cases where a rigid application would lead to great confusion.
Such exceptions become valid when approved by the Nomenclature Commission.

E. SUGGESTIONS AND RECOMMENDATIONS OF THE SOCIETY OF
AMERICAN BACTERIOLOGISTS

The preiiminarj^ report of the Committee of the Society of American
Bacteriologists on Characterization and Classification of Bacterial
Types (Winslow, Broadhurst, Buchanan, Krumwiede, Rogers and
Smith 1917) suggested the following to the Society:

We recommend to the Society of American Bacteriologists:

a. That the International Rules for Botanical Nomenclature be accepted by
the Society as governing bacterial terminology, with the exception that French,
English or German may be substituted for Latin in the diagnosis.

b. That the date of publication of the third edition of Zopf's Spaltpilze be
considered as the date for the beginning of bacteriological nomenclature for the
purpose of determining priority, with the exception of a list of genera conservanda
to be adopted by the Society at its 1918 meeting.

150 GENERAL SYSTEMATIC BACTERIOLOGY

c. That the Society take steps to present these recommendations to the next
International Botanical Congress, and if possible to secure favorable action
thereon by that body.

In the final report (1920) the following statement is made.

The following names are recommended for adoption as approved genera:

Acetobacter Fuhrmann Leuconostoc Van Tieghem

Actinomyces Harz Micrococcus Cohn

Bacillus Cohn Rhizobium Frank
Bacterium Ehrenberg ' Sarcina Goodsir

Chromobacterium Bergonzini Spirillum Ehrenberg

Clostridium Prazmowski Staphylococcus Rosenbach

Erythrobacillus Fortineau Streptococcus Rosenbach

Leptotrichia Trevisan Vibrio Mueller

Its work so far as possible being completed, we recommend that the Committee
on Characterization and Classification of Bacterial Types be discharged and that
a new Committee on Bacterial Taxonomy be appointed (1) to study and report to
the Society from time to time in regard to problems of nomenclature, including
such revisions of the nomenclature in the present report as may seem necessary;
and (2) to take the proper steps to secure action at the next International Botani-
cal Congress leading to the general ends contemplated in the 1916 recommenda-
tions of the Society:

a. That French, English or German may be substituted for Latin in the diag-
nosis of bacterial species.

b. That the date of publication of the third edition of Zopf's Spaltpilze (1883)
be considered the beginning of bacterial nomenclature for the purpose of deter-
mining priority, with the exception of a definite list of genera conservanda.

c. That such of the approved generic names specified above as may be found
to require such action be recognized as genera conservanda in bacterial taxonomy.

STATEMENT AS TO NOMENCLATURAL PRACTICE IN PRESENT

VOLUME

It would seem evident from the preceding discussion that the funda-
mental basis for nomenclature in bacteriology must be the International
Botanical or Vienna-Brussels Code. However, it is quite apparent that
there are certain rules which have not been and cannot well be recognized
by bacteriologists, particularly the rule requiring that the specific diagno-
ses be published in Latin in order to be valid. It is also evident that
stability in bacteriological nomenclature must come through the appli-
cation of a type basis. Apparently the best that has been formulated
for botanists is that contained in the majority report of the Committee
on Botanical Nomenclature given above. We shall therefore utilize
the latter as a basis for naming the bacteria described. It should be
remembered that acceptance of the code of this report does not mean
abandonment of the International Code.

GENERAL SYSTEMATIC BACTERIOLOGY

151

Occasional reference will be made to the Zoological Code where organ-
isms have a doubtful status in the plant kingdom. It will also be used
to determine good usage where the Botanical Code is silent or
ambiguous.

CHAPTER III

NOMENCLATURAL STATUS OF NAMES WHICH HAVE BEEN APPLIED

TO GROUPS OF Bacteria of Higher Rank than Species

On the following pages is given alphabetically arranged a list of the
names which have been proposed for subgenera, genera, subtribes,
tribes, subfamilies, families, orders, and classes of bacteria, including
casual or vernacular terms which have had more or less extensive
recognition and have been confused with scientific names. In general
an attempt has been to give the original diagnosis Of the term, to
discuss its usage by bacteriologists, and to point out whether its use
apparently contravenes good usage or the rules of the code. In many
cases an opinion is given as to probable validity.

Acetimonas. A generic name for the vinegar bacteria proposed by
S. Orla- Jensen (1909, p. 312). This genus is listed as the fourth of the
family Oxydobaderiaceae, order Cephalotrichinae. The genus is first
described as follows:

Die Essigsaure bakterien sind, soweit bekannt, ebensowie die vorhergehen-
den Bakterien monotriche oder unbewegliche Stabchen, die sich auf der Ob-
erflache der Nahrfliissigkeiten zu einer Haut ausbreiten. Ich habe ihnen daher
den Gattungsnamen Acetimonas gegeben. Von den Schnellessigbakterien bis
zu den Essigbildern des Weines und des Bieres steigen die Ausspruche auf or-
ganische Nahrung. Bekanntlich gedeihen die Schnellessigbakterien (z. B.
B. Schutzenbachii) mit Aethylalkohol als einzige Kohlenstoff quelle. Es ist
jedoch kaum wahrscheinlich, dass Alkohol die erste Kohlenstoff- und Energie-
quelle war, die den Essigsaurebakterien hier auf der Erde zur Verfiigung stand;
dies sind eher Kohlenhydrate gewesen, welche sie ja auch in hoherem oder
geringerem Grade zu oxydieren im Stande sind. Nach meinem Untersuchungen
konnen die meisten Essigsaurebakterien sich mit Saltpeter als Stickstoffquelle
begniigen. Einzelne Arten (am starksten B. aceli) reduzieren nach liingerer
Zeit kleinere Mengen Saltpeter bis zum Ammoniak, eine Eigenschaft die auch
andere obligat aerobe Bakterien (z. B. Azotobacter und gewisse Heubacillen)
besitzen, und die zeigt, dass solche Bakterien ausser dem freien Sauerstoff auch
gebundenen verwenden konneii.

Later the same author (1909, p. 477) gave the following description:
"Bediirfen in der Regel nicht organischen N-Quellen. Sauerstoff-
bediirfniss positiv. Oxydiert Alkohol zu Essigsaure."

152

GENERAL SYSTEMATIC BACTERIOLOGY 153

It will be noted that no type species is designated. Of the two species
mentioned "B. Schiitzenhachii" is given first, and may be regarded as
the type.

Other names which have been applied in a more or less strict generic
sense to the group of acetic bacteria are Mycoderma (Persoon 1822,
p. 96), Ulvina (Kutzing 1837 ?), Umbina (NageU 1857, p. 760), Aceto-
hacier (Beijermck 1898 ?), Acetobacterium (Hoyer 1898, p. 870).

The organisms belonging to this group have commonly been placed
in the genera Bacillus and Bacterium by various authors.

The name Acetimonas was regarded as a synonym of Mycoderma
Persoon by Buchanan (1918, p. 45) and Winslow et al. (1917, p. 551),
and finally of Acetobacter Fuhrmann by Winslow et al. (1920, p. 201).

It is here included as a synonjTn of Acetobacter Beijerinck, q.v.

Acetobacter. A generic name proposed by Beijerinck (?) for the
group of acetic acid bacteria.

The exact time and method of publication is difficult to determine.

According to Enlows (1920, p. 11), the name is first found in Krai's
Sammlung v. Mikroorg. (Prague 1898, pp. 7 and 8) where Acetobacter
pastor ianus (Hansen ?), Beijerinck and A. aceti are listed as synonyms
of Bacterium Pasteurianum and Bad. aceti respectively. In the 1900
and 1904 editions these are likewise listed as synonyms of Bacterium
Pasteurianum and Bact. aceti respectively.

Beijerinck (1901, p. 219), m an article in which he describes several
genera of lactic bacteria at length, mentions Acetobacter as producing
catalase, in contrast to Lactobacillus which produces none.

It is of interest to note that in a translation (published in 1898) of a
Dutch paper (published in 1897) on the acetic bacteria, Beijerinck
uses the name Bacterium consistently for the species of this group.

Ludwig (1898, p. 870) in a review of Hoyer's (1898) dissertation on
the acetic bacteria uses the name Acetobacterium xylinum. Examina-
tion of the original is necessarj' to show whether this is a misprint.

The first adequate description of an organism placed definitely in
this genus thus far found is Acetobacter plicatum Furhmann (1905, p. 8).
It was this that led the Committee of the Society of American Bacteri-
ologists to ascribe the genus to Furhmann. If this is done, however,
his species A. plicatum would constitute the type.

Acetobacter melanoginum was described later bj' Beijerinck (1911,
p. 171).

The generic name Acetobacter was accepted by Winslow et al. (1920,
p. 201), for the acetic bacteria, displacing Mycoderma. They give the
following description :

154 GENERAL SYSTEMATIC BACTERIOLOGY

Cells rod shaped, frequently in chains, non-motile. Cells grow usually on
the surface of alcoholic solutions as obligate aerobes, securing growth energy by
the oxidation of alcohol to acetic acid. Also capable of utilizing certain other
carbonaceous compounds, as sugar and acetic acid. Elongated, filamentous,
club shaped, swollen and even branched cells may occur as involution forms.

The type species designated by Winslow et al. was Acetobacter aceti
(Thompson 1852) Committee.

It is probable that the correct designation of the type species would
be Acetobacter aceti Beijerinck.

Other generic names which have applied more or less strictly to this
group are Mycoderma (Persoon 1822, p. 96), Ulvina (Kiitzing 1837 ?),
Umbina (Nageli 1857), Acetobacterium (Ludwig ? 1898) and Aceti-
monas (Orla-Jensen 1909) q.v.

Buchanan (1918, p. 45) listed Acetobacter as a synonym of Myco-
derma. Bergey et al. include this genus as the sixth of the tribe Nitro-
bactereae.

In this treatise Acetobacter is recognized as a valid generic name with
Acetobacter aceti Beijerinck as the type.

Acetobacterium. A generic name apparently first used by Hoyer
(1898) as a designation for acetic bacteria. The original thesis is not
available, but the name Acetobacter xylinum is used by Ludwig (1898,
p. 870) in an extended review of Hoyer's paper. He also in the same
year apparently ascribed the name to Beijerinck in the following state-
ment:

Nach den Beobachtungen Beyerinck's wiirde der Leuconostoc Lagerheimii
mit dem Bacterium xylinu7n Brown zusammen in ein und dieselbe Gruppe der
Acetobacterien gehoren. Beyerinck bezeichnet ihn in lit. als Acetobacterium
xylinum var. Lagerheimii.

The only reference to such a conception thus far found in the writings
of Beijerinck is a footnote (1898, p. 211) to a brief description of Bac-
terium xylinum in which he says, "Hauptmasse des Schleims beim
Schleimflusse lebender Eichen Mldet." There is no use of the name
Acetobacterium.

It is probable that Acetobacterium should be regarded as a synonym
of Acetobacter.

Achromatiaceae. A family of the order Thiobacteriales proposed
by Buchanan (1918, p. 462) to include the three genera Achromatium,
Thiophysa and Hillhousia.

The diagnosis given is "Unicellular, large, motile (by means of
flagella ?) cells containing granules of sulphur (or in one form possibly

GENERAL SYSTEMATIC BACTERIOLOGY 155

oxalate), but no bacteriopurpurin." The family is recognized by
Bergey et at. (1923, p. 410) in this sense.

The generic type is AchromaUum oxaliferum Schewiakoff (1893, p. 1).

Achromatium. A genus of schizophytes proposed by Schewiakoff
(1893, p. 1) and tentatively placed by him with the bacteria.

The species described, Achromatium oxalijerum, was found in river
slime, by R. Lauterbom, in considerable numbers. In form the organ-
ism varies from nearly spherical in newly divided cells to ellipsoidal.
In size the organism is larger than any other form previously described
among bacteria; cells about to divide are 15 to 43 /x in length, diameter
9 to 22 fx. Occasional!}' longer cells are found. The cells are closely
packed with large granules which were at first interpreted as com-
posed of sulfur. The use of various solvents and microchemical tests
indicated them to be, however, of calcium oxalate. When the granules
are dissolved the cell is found to contain protoplasm of a coarse alveolar
structure. The cells are motile, but flagella were not demonstrated.
Cell division is described as the result of constriction, as among flagel-
lates, rather than by the fission characteristic of most bacteria.

Mig-ula (1900, p. 1038) tentatively added Achromatium Mulleri
(Warming) IVIigula to this genus. The organism was originally de-
scribed by Warming (1876) as Manas Mulleri. The descriptions make
it probable that this organism is misplaced in Achromatium, and belongs
with the sulfur forms. Migula gives the following description of the
genus.

Zellen gross, eiformig cylindrisch mit grobkornigem Inhalt, der jedoch nicht
aus Schwefel, sondern aus Oxalsaure und einem Calciumsalz besteht. Bewegung
vorhanden, doch ist eine Geissel als Bewegungsorgan nicht nachgewiesen.
Teilung von der Bakterien abweichend, durch Einschniirung, wie bei den Flagel-
leten.

Achromatium oxaliferum Schewiakoff was subsequently described
independently by Frenzel (1897, p. 801) as Modderula hartwigi (from
the name "JModder" given by North German fishermen to the slimy
river bottoms). Lauterbom (1898, p. 95) called attention to the
previous description of Achromatium, and agreed with Schewiakoff in
placing the organism with the bacteria. Frenzel found this form to
vary from 12 to oOju in length. He was able to find no adequate ex-
planation of the motility. The cell membrane he describes as firm,
almost doubly contoured, clear, colorless and structureless. He in-
terpreted the granules contained within the cell as sulfur. The organ-
ism was not cultivated in artificial media, although it continued to

156 GENERAL SYSTEMATIC BACTERIOLOGY

multiply for a time in the laboratory. He concluded that the organ-
ism is most closely related to the bacteria, but that it constitutes a very
distinct type.

It would appear that the genus Achromatium Schewiakoff is valid,
with the type species A . oxaliferum Schewiakoff, It is listed by Smith
(1905, p. 174) as a doubtful bacterial genus and in another list as a
rejected name. Migula (1904, p. 128) states that he appends the
genus Achromatium to the bacteria, although (because of the cell
dimensions) he considers the relationship distant. A careful rechecking
of the work of Schewiakoff on the question of the composition of the
granules would be helpful in determining the affinities of this organism.

Buchanan (1918, p. 462) included this genus as the type of the familj'-
Achromatiaceae with the following description:

Cells large, nearly spherical in newly divided cells to ellipsoidal, 15 to 43 by
9 to 22/i. Cells closely packed with large granules, at first interpreted as sul-
phur, but later interpreted as calcium oxalate. When granules are dissolved,
cells show coarse alveolar structure. Cells are motile, flagella not demon-
strated. Cell division resembles the constriction of flagellates rather than the
fission characteristic of bacteria.

This generic diagnosis was also used by Bergey et al. (1923, p. 410).

In this treatise Achromatium is accepted as a valid bacterial genus.

Achromobacter. A generic name proposed by Bergey et al. (Com-
mittee Soc. Am. Bact., 1923, p. 132) for the single genus of the tribe
Achromobacter eae. The generic description is:

Non-pigment forming (at most no pigment formed on agar or gelatin) rods,
occurring in water and soil. Motile or non-motile. Gram-negative.
The type species is Achromobacter Liquefaciens (Frankland).

In all some 51 species are included in the genus.
Achromobactereae. A name used by Bergey et al. (1923, p. 132) for
the second tribe of the famil}^ Bacteriaceae. The tribal description is:

Rods, small to medium in size, occurring principally in water and soil. Form
no pigment on agar or gelatin but may produce a brownish growth on potato.
Cultural characters variable. Motile or non-motile. Gram-negative.

One genus only is included, Achromobacter.

Acidobacteriaceae. The first family of the order Peritrichinae of
Orla-Jensen (1909, p. 343). It includes seven genera: Denitrobacterium,
Bacterium, Propionibacterium, Caseobacterium, Streptococcus, Micro-
coccus and Sarcina. It includes organisms which usually cause acid

GENERAL SYSTEMATIC BACTERIOLOGY 157

fonnatioii from carbohydrates, which when motile, have peritrichous
flagella, which are not obUgate anaerobes and which do not typically
form alkalies by splitting of proteins. The genus Denitrobacterium,
characterized by large denitrifying powers, does not strictly belong in
this family, but is intermediate between the other genera and the
family Luminihacteriaceae of the preceding order Cephalotrichinae.

The genera of the family Acidobacteriaceae as recognized by Orla-
Jensen may be differentiated by the following key :

A. Primarily denitrifying rods. Genus 1. Denitrobacterium.

B. Not primarily denitrifiers.

I. Cells rod shaped.

a. Producing succinic acid. Colon group.

Genus 2. Bacterium.

b. Producing lactic acid. Genus 4. Caseobacterium.

II. Cells spherical.

a. Producing propionic acid.

Genus 3. Propionibacterium.

b. Not producing propionic acid.

1. Cells in chains. Genus 5. Streptococcus.

2. Cells irregularly arranged.

Genus 6. Micrococcus.

3. Cells in packets. Genus 7. Sarcina.

Orla-Jensen (p. 340) suggests that the additional genera Sporosarcina
for sarcina forms that develop spores and Peptonococcus for the lactic
acid bacteria that form peptones from proteins should be added.

The name apparently has not been used by subsequent writers.

It may be noted that the family name Acidobacteriaceae is not derived
from any of the component genera, and is therefore incorrect in form,
and may be regarded as invalid.

Actinobacille. A casual name given by Ligni^res and Spitz
(1904, p. 454) to a group of bacteria related to Actinomyces. The
French designation actinobacille was used apparently as a translation
of the original Spanish term actinobacilo {q.v.) by Lignieres and Spitz
(1902, p. 169). This is the form later designated by the generic name
Actinobacillus (q.v.) by Brumpt (1910, p. 849).

The description given by Lignieres and Spitz is as follows:

L'agent specifique de I'actinophytose h actinobacille se presente, dans les
cultures sous I'aspect d'un microbe parfois k peine plus gros que celui du cholera
des poules. Dans les premieres cultures, il est nettement bacillaire;plus tard,
surtout sus gelose, il affecte la forme du cocco-bacille ou de diplocoque; dans
les cultures en bouillon serum, on observe I'aspect streptobacillaire. Enfin,

158 GENERAL SYSTEMATIC BACTERIOLOGY

dans les vieilles cultures, principalement en bouillon addition^ de serum aggluti-

nant, on trouve souvent des formes d'involution les plus bizarres

Jamais on ne trouve de filaments dichotomises comme les autres actinophytoses
deja signales ici.

Enlows (1920, p. 11) gives the following characterization:

Pleomorphic. Sometimes rodlike, sometimes coccuslike, in pairs; also strep-
tobacillary forms occur: 0.15/^ to 1.25/i in length by 0.4/i; non-motile: no spores;
gram-negative; bipolar staining. The final stage of growth gives rise to little
masses, in which the organisms are pressed closely together, giving the ray like
aspect. These masses consist of a central germinative zone and an outer or
vegetative zone. Cause of actinobacillosis in cattle.

This is to be regarded as a casual name for the genus Aciinobacillus.

Actinobacillus. A generic name given by Brumpt (1910, p. 849)
to the organism causing "Actinobacilosis" and termed "Actinobacilo"
by Lignieres and Spitz (1902, p. 1G9). The organism was accorded no
specific name by Lignieres; it was named by Brumpt in his honor,
Actinobacillus Lignieresi. This species therefore constitutes the generic
type.

The organism is the cause of an infection in cattle and sheep termed
actmobacillosis. The lesions resemble closely those of actinomycosis.
In culture of the organism on solid media small, transparent colonies
appear in twenty-four hours. They consist of small diplococcus-like
bacilli or of streptobacilli, resembling the fowl cholera organism when
grown in broth in their occurrence in long chains. Dextrose and lactose
are not fermented. Indol reaction is weak. The pus in the lesions
contains granules the size of a millet seed. Microscopically these show
at their peripheries swollen, finger shaped, branched forms whose
central ends are pointed. The filaments are Gram-negative. The
central portion does not contain a branched mycelium. Isolated
threads are not found in the pus.

Enlows (1920) states "Type species (monotypy). A. lignieresi.
Streptobacillary^ bacillary or coccoidal in form. Gram-negative.
Never filamentous."

Merrill and Wade (1919, p. 64) state that this name was given to a
supposed subtype of Discomyces; but that the distinction has not been
recognized, and by most authors the name is considered a synonym.

Buchanan (1918, p. 404),Winslow et al. (1920, p. 198) and Bergey
et al. (1923, p. 338) recognize the genus with the following diagnosis:

Filament formation, resembling streptobacilli. In lesions no mycelium is
formed, but at peripheries finger shaped branched cells are visible. Gram neg-
ative. Not acid fast.

GENERAL SYSTEMATIC BACTERIOLOGY 159

It is included in the family Actinomycetaceae.

Beijerinck (1914, p. 96) renamed his Bacillus oUgocarhophilus as
Actinohacillus oligocarbophilus and his Actinomyces (Streptothrix) paulo-
trophus as A. paulotrophus. No indication is given of the previous use
of this generic name by Brumpt. The organisms described are prob-
ably sufficiently unlike those causing actinobacillosis in cattle to pre-
vent their inclusion in the same genus. Probably Beijerinck's Actino-
bacillus is to be regarded as an invalid homonym. His description of
the genus and the two species follows:

Drittens, die Gattung Actinohacillus, welche zu der Familie der Actinomy-
ceten gehort und desshalb typisch unbeweglich ist. Unterscheidet sich von der
Neumann und Lehmann aufgestellten Gattung Mycobacterium durch das vol-
standige Fehlen der Verzweigung, sodass man nur Stabchen oder Faden findet.
Erzeugt die characteristische treibende "Kahmhaut" auf der Oberflache der
nitrifizirenden Fliissigkeiten. Darin finden sich zwei Arten namlich:

a. Actinohacillus oligocarbophilus welche sich ernahren kann von den Koh-
lenstoffverbindungen der atmosferischen Luft und dann das "Kahmpilzmerkmal"
zeigt; anderseits auf den verschiedensten organischen Nahrboden wachst ohne
das "Kahmpilzmerkmal." Letzterer Zustand auf Kieselplatten zuriickgeimpft
zeigt das "Kahmpilzmerkmal." Doch kann das Merkmal verloren gehen durch
lange fortgesetzte saprophytische Lebensweise. Verfliissigt Nahrgelatine nicht.

b. Actinohacillus paiilotrophus. Erzeugt auf den nitratierenden Flatten
schimmelartige Kolonien mit "Lufthyphen;" besteht jedoch mikroskopisch
anscheinend aus gleichartigen Stabchen und Faden. Wachst durchaus nicht
bei Gegenwart organischer Substanz.

Viertens, die Gattung Actinomyces wovon verschiedene Arten, in geringer
Anzahl in den "Kahmhauten" von Actinohacillus vorkommen konnen, daraus
jedoch bei den Ueberimpfungen bisweilen giinzlich verschwinden.

If generic rank is to be accorded organisms of this type, the name
Actinohacillus Brumpt would appear to be valid, otherwise it should be
suppressed as a synonym. Organisms of this type have probably been
included by various writers under the generic names Actinomyces,
Bacterium and Bacillus.

It is possible that Actinohacterium Haass should be regarded as an
invalid synonym.

In the present volume the generic name Actinohacillus is accepted in
the sense of Brumpt.

Actinobacilo. A Spanish casual name first used by Lignieres and
Spitz (1902, p. 169) for the organisms later named Actinohacillus (q.v.).

Actinobacter. A generic name for certain milk bacteria proposed
by Duclaux (1882, p. 110).

160 GENERAL SYSTEMATIC BACTERIOLOGY

The first species described (the type species) is Adinohacter poly-
morphum Duclaux. In milk the organism occurs as rods 2 to 3m in
length, each surrounded by a hyaline capsule 5 to 6/i in length. At
first the milk retains its normal appearance, and gradually becomes
gelatinous and at last viscous. The opacity is in part lost, the trans-
parency increases, the coagulum settles out and disappears. Finally
the transparent liquid shows little more viscosity than the normal milk.
In the later stages the organisms are 2 to 3ju long by 1^ in diameter and
without capsule. In Liebig's bouillon there are no capsules, the cells
may attain a length of 8 to IOjjl. In a glycerine medium the capsules
are present. The capsule does not disappear as in milk, "sans doute
parce que le liquide reste acide." In sucrose medium the growth and
appearance is much as in glycerine. Gas (carbon dioxide and hydro-
gen) were formed from sugar, but not from glycerine.

Maggi (1886, p. 174) includes Adinohacter as a valid genus. It
appears evident from the characterization of this organism that it is
a member of the colon group of bacteria, probably closely related to
organisms of the type of Baderium ladis aerogenes. The description
is too indefinite however to allow of accurate diagnosis at the present
time. It is included by Lohnis (1911) with the Baderium pneumoniae
group. It is rejected as invalid by E. F. Smith (1905, p. 174).

Enlows (1920, p. 12) characterizes the genus as follows:

Type species (monotypy). A polymorphus. Polymorphic. Non-motile,
very thin small rods 2 to 3/i long, surrounded by a hyalin, oval or round,
gelatinous envelope 5 or 6/i long. The organism gradually passes over into very
short cylinders not more than Iju long, which are not capsulated. No capsule
ever forms in Liebig's bouillon, where the organism may reach 10/x in length.
Aerobic. Multiplication by transverse division. Transforms the casein of
milk into a water-soluble albuminoid, and milk-sugar into alcohol and acetic
acid. Found in milk.

If the group of colon bacilli or colon-typhoid bacilli are to be accorded
generic rank the name Adinobader must be considered as one which
might be used in its designation. It is questionable however whether
the type species can ever be identified from the description, and prob-
ably it is unwise to use as a genus name one in which the type species
is so uncertain. Other bacteria have apparently not been placed in the
genus by other authors. It is evident therefore that without emenda-
tion this name can scarcely be regarded as valid. It may be listed as
a synonym of Baderium {q.v.).

GENERAL SYSTEMATIC BACTERIOLOGY 161

Actinobacterium. A generic name proposed by Haass (1906,
p. 180) to apply to two strains of organisms termed by him Actino-
myces Klinik I and II which were found to differ from all of eleven other
types studied. These were isolated from pus from cases of human
actinomycosis. They were similar to the forms described by Wolff
and Israel, by Silberschmidt and by Wright as anaerobes. The organ-
isms had short cells, somewhat branched, and were Gram-positive.
Haass notes that Lignieres and Spitz previously used the generic
name Actinobacillus for a similar type. He believes the genus to be
intermediate between Actinomyces and Corynebacterium. Sampietro
(1908, p. 331) described an Actinobacterium israeli var, spitzi.

No species of the genus was named by Haass, if valid therefore it
should be credited to Sampietro. It may perhaps be regarded as a
synonym of Actinomyces.

Reitz (1906, p. 731) apparently confused this name with Actino-
bacter (q.v.) and refers to Actinobacterium lactis viscosum.

Actinocladothrix. A generic name ascribed to Affanassieff by Levy
(1899, p. 2), by Schlegel (1913, p. 303), and by others. It seems
probable that they are in error in giving the name generic rank. Affanas-
sieff (1888, p. 79) himself gave the name Bacterium actinocladothrix to
an Actinomyces. De Toni and Trevisan (1889, p. 928) also give the
synonym Bacterium actinocladothrix Afanassjew 1888 to Nocardia
Actinomyces Trevisan (Actinomyces bovis Harz.) Brumpt (1910, p. 844)
gives the name the same specific form. The use of the name Actino-
cladothrix as a generic designation is therefore based upon false premises.
The correct generic designation would seem to be Actinomyces.

Actinococcus. A name proposed by Kiitzing for a genus of algae,
included by Pfeiffer (1870, p. 11) in the tribe Chaetophorae.

Beijerinck (1914, p. 196) suggested the generic name Actinococcus
to apply to a bacterial species A. cyaneus. Beijerinck isolated this
organism from garden soil on a medium particularly adapted to the
culture of Actinomyces, containing glucose, calcium malate, ammonium
sulphite, dipotassium phosphate and agar. Gelatin was liquefied slowly,
and agar made alkaline by the formation of ammonium carbonate. In a
medium with peptone the color is rose, with glucose and nitrate of potas-
sium or ammonium it remains violet. Ammonium acetate is very
favorable for the production of the violet color. The pigment is blue
with alkalies and red with acids. The organism he believes belongs with
the genera Corynebacterium, Mycobacterium and Actinomyces. This
relationship is indicated by the dry colonies, the disposition of the cell

162 GENERAL SYSTEMATIC BACTERIOLOGY

in radiating rays, and the branched appearance of the rays. Later
(1914, p. 99) he mentions the creation of the generic name.

It would seem that the prior use of Actinococcus for a genus of algae
would invalidate its use for a genus of bacteria.

Actinomyce. A generic name proposed by Meyen (1827, p. 442) for
a fungus species Actinomyce Horkelii. The genus was placed in the new
group Hydrotremellinae. The generic description follows:

Sporodochia, cellulis hyalinis simplicibus, enormiter et multipliciter ramifi-
cantibus sporis impletis, substantiae uniformi gelatinosa hyalina induta.

This generic name is of importance in bacteriology only because it
was given prior to the use of Actinomyces by Harz for an entirely dis-
tinct organism. In many references the spelling is made identical,
but it will be noted that there is a difference. For example Streinz
(1862, p. 3) in his "Nomenclator fungonim" writes "Actinomyce Meyen
(Strahlenpilz) eine neue Pilzgattung."

Perroncito (1879, p. 35), Musgrave, Clegg and Polk (1908, p. 458),
Merrill and Wade (1919, p. 65), Chalmers and Christopherson (1916,
p. 227) and others have urged that this use precludes the validity of
Actinomijces Harz, q.v.

It is probable that Actinomyce Meyen should not render invalid
Actinomyces for the following reasons:

1. The spellings are different. The botanical code expressly provides
that names differing only by a single letter may both be valid if both
do not come within the same family, and are not likely to give rise to
confusion.

2. No other author apparently has used Actinomyce Meyen, and it
may be said to be "universally regarded as invalid."

Actinomyces. The generic name Actinomyce was used by Meyen
(1827, p. 442) for a genus of fungi belonging to the Hydrotremellinae
Meyen, with one species A. Horkelii Meyen. For reasons why this
should not be regarded as invalidating the subsequent use of Actino-
myces, see Actinomyce.

In 1877 the name Actinomyces was applied to a genus of thread
bacteria by Harz (1877, p. 125). The material containing the organism
was sent to Harz by Bollinger. It consisted of granules secured from
pus from cattle affected by "lumpy jaw." The granules were found to
consist of slender filaments, irregularly branched, radiating from the
center, and with the ends of the filaments in the form of refractive
swellings. The name Actinomyces bovis was given it.

GENERAL SYSTEMATIC BACTERIOLOGY 163

In the following year, Rivolta (1878, p. 201) used the generic designa-
tion Discomyces (q.v.). The name Actinomyces bovis Harz, however,
was recognized by Rivolta in 1884. At this time he differentiated
between A. bovis and two other species which he termed Discomyces
equi and D. pleuriticus.

Actinomyces was used as a generic name by several authors during the
next decade. Perroncito (1879, p. 35) noted that the name Actinomyces
should be changed because of the previous use by Meyen of Actinomyce
for one of the Coniomycetes. Hertwig (1886, p. 365) described an
Actinomyces musculorum, which was further studied by Duncker
(1887, p. 224). Schroeter (1886, p. 174) recognized the genus Actino-
myces Harz, regarding Discomyces Rivolta as a synonym. He gives
the following generic description :

Faden sehr dtinn, etwa bis 0.5 mm. lang, um einen festen Kern, welcher in
den Faden durchzogen wird, strahlig ausgebreitet, mit unregelmassig abgehenden
Aesten, an den Enden in keulenformige, stark lichtbrechende Auschwellungen
ubergehend, welche Gliederung zeigen.

Trevisan (1889, p. 927) recognized the fact that an organism named by
Cohn (1875, p. 186) Streptothrix Foersteri was closely related to the
Actinomyces bovis Harz. He concluded that neither Actinomyces
Harz, nor Streptothrdx Cohn were tenable, the former because of prior
use by Meyen (1. c.) and the latter by Corda (1839, p. 23). He
accordingly named the genus Nocardia, with Nocardia Actinomyces
Trevisan as one of the five species. Sauvageau and Radais (1892, p.
242) suggested as a result of comparing the genus Streptothrix of Cohn
with other known Hyphomycetes, that this genus should be merged with
the Oospora of Wallroth (1837, p. 182). Several authors have used
this generic name. Lindau (1910, p. 720) as recently as 1910 reaches
the conclusion that this form is most closely related to Oospora.

The name Actinomyces has been used as a generic designation by
manj^ authors. Ludwig (1892, p. 3) defined the genus as having
branched filaments, the branches swollen at the tips. Terni (1894, p.
79) noted the previous use by Corda of Streptothrix and accepted
Actinomyces. Gasperini (1895, p. 82) concluded that it is valid and
should replace Streptothrix Cohn, Discomyces and Pleurimices Rivolta,
Bacillus Nocard, Micromyces Griiber and Oospora Sauvageau and
Radais. Lachner-Sandoval (1898) made a careful stud}- of the nomen-
clature of the genus and concluded the right generic designation to be
Actinomyces. Levy (1899, p. 1) confiraied his conclusions. Berestnew
(1899, p. 390) concluded that on botanical grounds the name is tenable,

164 GENERAL SYSTEMATIC BACTERIOLOGY

and that it is a most appropriate designation both because it indicates
a most important characteristic of the colonies on artificial media and
because it shows relationship to the fungi. Lehmann and Neumann
(1896) in the first edition of their Grundriss use the name Oospora,
but in later editions they have followed Lachner-Sandoval in the use of
Actinomyces.

Gedoelst (1902) concludes Actinomyces to be invalid, and substitutes
for it Rivolta's term, Discomyces. This point of view is also taken by
Moore and Wade (1919, p. 55.)

Wright (1904, p. 349) concludes that the name Actinomyces should be
strictly limited to the parasitic forms which produce rays in tissues,
and do not form chains of conidia or spores on artificial media. For the
forms which do not show the clubbing in tissues and which develop
chains of conidia he used the name Nocardia Trevisan as emended by
Blanchard (1896, p. 853). Jordan (1910, p. 411) used the same basis of
differentiation. The genus Actinomyces has also been recognized by
Orla-Jensen (1909, p. 334) and by Schlegel (1913, p. 302). The latter
author emphasized the formation of a true branched mycelium, re-
production by conidial chains, and by the presence of the rayed form
in the body tissues. Petruschky (1913, p. 270) gives a very confused
discussion of this nomenclature. He concludes that Actinomyces
should be strictly limited to the clubbed or ray forms in tissues, and
that others should be termed Streptothrix. Pinoy (1911) introduced
the new generic name Cohnistreptothrix for organisms of the type of
Cohn's Streptothrix foersteri. In a later article (1913, p. 929) he reviews
the use of the various generic names proposed, and concludes that
Streptothrix must be reserved for the hyphomycete of Corda, and that
Actinomyces is equally untenable. Discomyces he states was not pro-
posed originally as a strict generic designation, but as a common name
and furthermore that it resembles in form too closely the group name
Discomycetes of the Pezizales. He quotes the action of the botanical
section of the first International Congress of Comparative Pathology,
which decided to adopt the generic name Nocardia of Trevisan. He
divides the old genus Actinomyces into two, Nocardia with A^. bovis
as the type, and Cohnistreptothrix with C. foersteri and C. Israeli as the
best known species. Nocardia includes those forms which are aerobic,
grow readily on artificial media and produce arthrospores. Cohni-
streptothrix on the other hand, includes those forms which are anaerobic
or at least microaerophilic, are relatively more difficult of cultivation
and do not produce arthrospores. This author comes to the conclusion

GENERAL SYSTEMATIC BACTERIOLOGY 165

that the presence or absence of "clubs" when growing in tissues is not
diagnostic. These are the result of certain interreactions between
parasite and host, and may be produced in either genus under the right
conditions.

Buchanan (1918, p. 405) characterized the genus as follows:

Branched filaments, resembling mycelium, breaking up into segments which
may function as conidia. Usually parasitic. Clubbed ends conspicuous in
lesions. Not producing aerial hyphae or conidia.

The type species is Actinomyces bovis Harz, the cause of bovine
actinomycosis.

Castellani and Chalmers (1919, p. 1041) reject Actinomyces in favor
of Nocardia. Waksman (1919) in his monographic treatment of the
group accepts the generic name Actinomyces as does also Lieske (1921,
p. 5).

The description used by the "Committee" of the American Society
of Bacteriologists (1920, p. 198) and by Bergey et at. (1923, p. 339)
follows :

Organism growing in form of a much-branched mycelium, which may break
up into segments that function as conidia. Sometimes parasitic, with clubbed
ends of radiating threads conspicuous in lesions in animal body. Some species
are microaerophilic or anaerobic. Non-motile.

The type species is Actinomyces bovis Harz.

Merrill and Wade (1919, p. 63) insist upon the non-vahdity of
Actinomyces and the validity of Discomyces.

The claim of legitimacy for Actinomyces as a generic name for the
organism causing lumpy jaw and other similar affections is menaced by
two facts: First, the name Actinomyce was used by Meyen in 1827 for
an entirely distinct fungus; Second, the generic name Streptothrix
Cohn has priority. Probably the best analysis of the situation is that
which has been furnished by Breed and Conn (1919, p. 585; 1920, p.
489). They say (1919, p. 594)

Two attempts have already been made to establish the validity of a generic
name for this group of organisms through legislative action both of which must
be regarded as abortive. The first was taken by a Committee of the English
Society of Pathologists who, as reported by Foulerton (1912, p. 304), approved
the term Streptothrix Cohn in ignorance of the general and wide usage of Strep-
tothrix Corda. The second was taken by the Botanical Section of the First
International Congress of Comparative Pathology according to Pinoy (1913,
p. 933) and confirmed by him in a letter dated September 9, 1918. The name ac-

166 GENERAL SYSTEMATIC BACTERIOLOGY

cepted was Nocardia. The official record of the Congress however contains no
reference to this action which is stated to have been taken during the discussion
of a paper by Potron (1912). As this action ignores the stronger claims of Ac-
tinomyces and Discomyces, and does not appear in the official record, it cannot be
regarded as final.

And further :

Because of confusion between Streptothrix Corda 1839 and Streptothrix Cohn
1875 and the general use of the former term by mycologists, the latter term should
be generally disregarded. xVccording to the International Rules of Botanical
Nomenclature, the limited use of the term Actinomyce by Meyen in 1828 and 1832
is not sufficient to invalidate the generally used Actinomyces Harz 1877 provided
the latter is accepted as a genus conservandum by an International Botanical Con-
gress. The continued use of the latter term is therefore recommended. The
type species of the genus is A. hovis Harz.

Later they note that both botanical and zoological codes provide for
the retention of generic names which differ only by a single letter
(International Botanical Code, Chapter III, Article 57). They note
further etymological differences between Actinomyce and Actinomyces,
(1920, p. 490).

Although the stem words from which Actinomyce and Actinomyces are derived
have identical meaning in the original Greek, " myce " is derived from the less
commonly used feminine word, hvkt^, while "myces" comes from the masculine
noun, fivKTis. Thus the two generic terms in question ought not to be regarded
as homonyms as is done by Merrill and Wade. This view we find has already
bean expressed by Giissow (1914) in a paper which we had overlooked, and is
confirmed by those authorities with whom we have consulted. This being the
case legislative action by an International Congress is unnecessary. Actinomyces
Harz is valid without such action and should be retained rather than Discomyces
Rivolta.

The generic name Streptothrix Cohn which has been held by some
writers to have priority over Actinomyces is clearly invalid. Corda's
genus Streptothrix is well characterized both by description and figure,
it has had additional species described, and is generally recognized in
classifications of the Hyphomycetes. The genus Oospora Wallroth
includes forms which are quite unrelated to Actinomyces; these forms
should therefore not be ascribed to it.

A real difficulty also presents itself when an attempt is made to pick
the type of the genus. It would seem certainly that to it the name
Actinomyces hovis should be given. Harz did not publish cultural
characters. It is impossible to determine with certainty just what his

GENERAL SYSTEMATIC BACTERIOLOGY 167

species was. Bostroem cultivated an aerobic type which produced
spores. Wolf and Israel described an anaerobic asporogenous tj'pe.
Wright and Pinoy have both shown the latter to be far more common.
The probabilities are that it was this form that was observed by Harz.
It would seem logical therefore to apply to it the name Actinomyces
hovis. Pinoy (who accepts Nocardia instead of Actinomyces) insists
that the organism described by Bostroem, i.e., the aerobic spore pro-
ducing form be taken as the type. Wright states, "I think that the
generic name Actinomyces should be restricted to microorganisms with
the biological characters described in this paper (i.e., the Wolf-Israel
type.)" Certainly to call the organism most frequently associated with
lumpy jaw in cattle anything other than .4. hovis would prove to be
confusing.

The difficulty is even more apparent and its solution more important
if the genus is to be split into two. Wright uses Actinomyces for the
anaerobic sporeless foims, and for the aerobic conidia formers the name
Nocardia, following the emendation of the genus by Blanchard (1896,
p. 856). Pinoy, on the other hand, uses the designation Cohnistrepto-
thrix for the forms termed Actinomyces by Wright, using the name
Nocardia in Wright's sense.

It would appear, therefore, that the demands of priority would be
satisfied by Wright's use of the terms. If all are to be included in a
single genus, it should be Actinomyces, if two genera they should be
Actinomyces and Nocardia. Cohnistreptothrix is to be regarded as a
sjmonjTn of Actinomyces in the narrow sense. The generic names
Streptothrix and Oospora should not be used for this group.

Actiaomycetaceae. A family name suggested by Buchanan (1918,
p. 403) as the single family of the order Actinomycetales. The Com-
mittee of the Society of American Bacteriologists (1920, p. 198) have
suggested its use as the name of one of the two families of the Actino-
mycetales, the other being Mycobacteriaceae. The Committee description
is "Filamentous forms often branched and sometimes formed mycelia.
Conidia sometimes present. Some species parasitic." This description
is also used by Bergey et al. (1923, p. 338).

In the present volume the recommendation of the Committee is
followed.

Actinomycetales. A designation suggested by Buchanan (1917, p.
162) for the order of the mold bacteria. The original description
follows :

Mold-like organisms, not t\T)ically water forms, saprophytic or parasitic.
Sheath not impregnated with iron, true hj'phae with branching often evident,

168 GENERAL SYSTEMATIC BACTERIOLOGY

conidia may be developed, but never endospores. Without granules of free
sulphur and without bacteriopurpurin. Never producing a pseudoplasmodium.
Always non-motile.

The description was emended by the Committee of the Society of
American Bacteriologists to read as follows:

Cells usually elongated, frequently filamentous and with a decided tendency
to the development of branches, in some genera giving rise to the formation of
a definite branched mycelium. Cells frequently show swellings, clubbed or ir-
regular shapes. No pseudoplasmodium. No deposits of free sulphur or iron.
No bacteriopurpurin. Endospores not produced, but conidia developed in some
genera. Usually Gram-positive. Non-motile. Some species are parasitic in
animals or plants. Not water forms. Complex proteins frequently required.
As a rule strongly aerobic, (except for some species of Actinomyces and the gen-
era Fusiformis and Leptoti icMa) and oxidative. Growth on culture media often
slow; some genera show mold-like colonies.

This description is also used by Bergey et at. (1923, p. 337).

The committee recognized two families as belonging to this order,
Actinomycetaceae and Mycobacteriaceae. The committee's suggestion
is followed in the present volume.

Actinomycetes. This family designation of the thread fungi was
probably first proposed by Balbiani (1886, p. 542). Later Lachner-
Sandoval (1898) included in it the single genus Actinomyces Harz.
Lehmann and Neumann (1901, p. 127) include within the family three
genera, Corynehacterium L. and N., Mycobacterium L. and N., and
Actinomyces Harz. They give the following description of the family.

Delicate thread organisms, without chlorophyll, with true branching, in
some cases with an abundant branched mycelium and the formation of conidia.
Young cultures often show only unbranched rods resembling bacteria which
can in no way be differentiated from the ordinary fission fungi. According to
many authors there is a tendency to the formation of clubs or knobs at the ends
of the threads.

The three genera may be differentiated by the following key:

A. Cultures showing ordinary bacterial characters, flat or medium, micro-

scopically rods with swollen ends. Corynehacterium L. & M.

B. Cultures on solid media more or less folded.

I. Usually short slender rods only, seldom short branched filaments,
without aerial mycelium and without aerial conidia. Acid fast —
Mycobacterium L. & N.
II. Mycelial filaments long, often bent, without sheath, with true branch-
ing. Many species produce conidia or aerial hyphae. Not acid
fast — Actinomyces Harz.

GENERAL SYSTEMATIC BACTERIOLOGY 169

Orla-Jensen (1909) gives Actinomycetes as the name of the second
family of the bacterial order Cephalotrichinae. He includes in it four
genera, Rhizomonas Jensen, Corynemonas Jensen, Mycomonas Jensen,
and Actinomyces Harz. The designation has been extensively used in
the literature as a group name.

It would seem that the form Aciinomycetaceae would better fit no-
menclatural usage in accordance with Article 21 of the botanical code,
and in this form would be a valid family name.

Aerobacter. A generic name proposed by Beijerinck (1900, p.
198) for certain gas producing bacteria of the so-called "colon" group.
In sugar solutions all are facultative anaerobic, all ferment dextrose
and levulose with the formation of levo-rotatory lactic acid and usually
with production of gas as well. The gas is a mixture of carbon dioxide
and hydrogen. Sulfates are never reduced, while nitrates are readily
reduced with formation of nitrites, but never of ammonia. No spores
are formed. The organisms are easily killed by heating to 65°C. The
cells are frequently motile, either peritrichous or monotrichous. The
temperature optimum is about 28°C. The following are the best
known species which he lists.

Aerobacter aerogenes {Bacillus lactis aerogenes Escherich)
A. coli (with many varieties, best known, commune)
A. viscosum
A. liquefaciens (Digests gelatine, monotrichous)

Buchanan (1918, p. 53) used this as a subgeneric designation for
the colon group of the genius Bacterium, with the following diagnosis:
"Fermenting both glucose and lactose with formation of both acid and
gas. Pathogenicity sHght." The type species was designated as
Bacterium {Aerobacter) coli. This is probably to be regarded as an
error. A reading of the characterization of the genus by its author
emphasizes that Bacterium (Aerobacter) aerogenes is, instead, the type
for in the Hst and description of species the latter organism is first
given.

Beijerinck (p. 197) emphasizes that this group is to be regarded
as a true genus and not merely a physiological genus such as his
Photobacter

Aerobacter is rejected by Smith (1905, p. 174).

An Aerobacter tartarivorum was named by Nijdam (1907),

Enlows (1920, p. 13) gives the following characterization of the
genus.

170 GENERAL SYSTEMATIC BACTERIOLOGY

Facultative anaerobic organisms which give the "white lead test" with pro-
duction of sulfides, and certain related ferment organisms. No spores. Very
resistant to drying. Ferment dextrose and levulose with production of gas
and usually lactic acid. Sulfates not reduced. Nitrates reduced to nitrites,
but not to NH3.

Species. Bacillus coli communis Escherich, Includes here also B. liquefaciens
Tataroff, and Bad lactis aerogenes Escherich, the latter becoming Aerobacter
aerogenes.

"Bergey (1923, p. 205) recognizes the genus with the following
description :

Motile or non-motile rods, commonly occurring in the intestinal canal of
normal animals. Produce acetyl-methyl-carbinol.

The type species is Aerobacter aerogenes (Escherich) Castellani and Chalmers.

If the colon typhoid group is to be subdivided, it would seem that
Aerobacter should be regarded as a valid generic name with Aerobacter
aerogenes (Escherich) Beijerinck as the type.

Aerogenesbacterium. A generic name suggested by Orla-Jensen
(1921, p. 272). His statement follows:

The genus Bacterium will undoubtedly dissolve into several genera, of which
I may especially mention the Colibacterium, and Aerogenesbacterium. The reason
why I am now inclined, in contrast to my earlier opinion, to consider the coli-
and aerogenesbacteria as two different genera, is because they differ not only
in morphological, but, as later researches have shown, also in biological respects.
I have myself proved (1914), that the Aerogenesbacteria completely oxidize the
carbohydrates when the nutrient matter offers a sufficient buffer effect, and they
thus correspond with their name in forming more gas than do other bacteria,
:and Rogers, Clark and Davis (1914) have shown that in the gas developed by
the Colibacteria there is proportionately more hydrogen than in that developed
by the Aerogenesbacteria.

This generic designation is apparently a synonym of Aerobacter
Beijerinck. It is also questionable whether the indirect reference is
sufficient to establish a species. It is probable that Aerogenesbac-
terium aerogenes would be considered the type species, although this
combination was not used by Orla-Jensen,

Aethyl-BaciUus. A name used by Fitz (1878, p. 48) as a pseudo-
generic or casual designation for a rod shaped organism capable of pro-
ducing ethyl alcohol from glycerin. It is rejected by Smith (1905,
p. 174) and is invalid as a generic name.

Agonium. A generic name used by Oersted (1844, p, 44) to desig-
nate a marine organism, probably an alga (See De Toni. Sylloge

GENERAL SYSTEMATIC BACTERIOLOGY 171

Algarum 5, 684, 1907). It is placed questionably among the bacteria
by De Toni and Trevisan (1889, p. 938) with the following description:

Filamenta cylindrica, articulata, simplicia, basi ab apicc superiore distincta,
e puncto central! commune radiatim exorientia, caespites formantia. Sporae
(endosporae) maximae, ovales, singulae in unoquoque articulo obvientes.

The only species (type) is Agonium centrale Oersted.

It is doubtful whether this genus should be included with the
bacteria.

Aktinomyces. A German variant in the spelling of the generic
name Actinomyces, q.v. Apparently the first record of its use is by
Johne (1881, p. 143). It is probably invalid.

Albococcus. A genus of cocci proposed by Winslow and Rogers
(1906, p. 541) with Micrococcus pyogenes (Ros.) Mig. as the type.
The characteristics of the genus are given as follows :

Parasites. Cells in groups and short chains (never in packets). Generally
stain by Gram. Growth on agar streak abundant and porcelain white in color.
Sugars fermented with production of slight amount of acid. Gelatin lique-
faction and nitrate reduction may or may not occur.

Four species are noted. Albococcus pyogenes (Ros.) W. and R.,
A. rhenanus (Mig.) W. and R., A. candicans (Flugge) W. and R. and
A. canescens (Mig.) W. and R.

Later the Winslows (1908, p. 192) revised their list of species, giving
Albococcus pyogenes (Rosenbach) Winslow, Alb. epidermidis (Gor-
don) Winslow, Alb. candidus (Cohn) Winslow, and Alb. tetragenus
(Gaffky) Winslow.

Khgler (1913, p. 432) has added one species, Alb. ureae (Cohn, Flugge)
Kligler.

The genus Albococcus is one of the genera included by the Winslows
in the subfamily Paracoccaceae (g.v.)

To organisms of this group the generic name Micrococcus (q.v.)
was given by Cohn. The forms occurring in irregular masses or grape
like clusters, particularly those occurring in pus, were named Staphy-
lococcus {q.v.) by Rosenbach (1884, p. 19). The species described
were the golden and the white pus cocci, or Staphylococcus pyogenes
aureus and Staphylococcus pyogenes albus. On a later page, in a main
heading, the phrase "Staphylococcus aureus (mit oder ohne albu^)"
is used. The trinomial forms of the names first given would probably
bar the use of the generic designation Staphylococcus unless a species

172 GENERAL SYSTEMATIC BACTERIOLOGY

Staphylococcus pyogenes with two varieties aureus and alhus could
be conceived. However, the use by Rosenbach himself of the
binomial forms Staphylococcus aureus and Staphylococcus albus an-
swers all nomenclatural requirements. Migula (1894, p. 237) concluded
this genus should be merged with the older genus Micrococcus Cohn,
the species becoming M. aureus (Ros) Migula and M. pyogenes (Ros.)
Mig.

The Winslows concluded that these species should constitute the
types of the genera Aurococcus and Alhococcus respectively. They
discarded the name Staphylococcus (q.v.) apparently without sufficient
justification. The rules of botanical nomenclature state expHcitly
that when a genus is spUt into two genera the original generic name
must be retained for one genus. (See Art. 45, International Rules for
Botanical Nomenclature.) Inasmuch as Staphylococcus aureus was
the first to be described, the generic name Staphylococcus might ap-
propriately be retained for the genus of which this is the type. Ac-
cordingly the generic designation Albococcus for the white form would
appear consistent. It should be noted that the original specific desig-
nation of albus should be retained, the type of the genus then being
Albococcus albus (Rosenbach) and not Albococcus pyogenes (Rosenbach)
Winslow.

In the PreHminary Report of the Committee of the Society of Ameri-
can Bacteriologists (Winslow et al., 1917, p. 559), the genus Albococcus
is recognized with the following diagnosis:

Differs from Staphylococcus in forming more abundant surface growth of
porcelain white color, and in fact that liquefaction of gelatin when present is
less vigorous.

Buchanan (1917, p. 612) included Albococcus as a synonym of
Staphylococcus.

In the Final Report (Winslow et al., 1920) the genus Albococcus
is merged with Staphylococcus.

Enlows characterizes the genus as follows :

Parasites. Cells in groups and short chains (never in packets). Generally
stain by Gram. Growth on agar streak abundant and porcelain white in color.
Sugars fermented with production of a slight amount of acid. Gelatin lique-
faction and nitrate reduction may or may not occur.

Type species (original designation). A. pyogenes (M. pyogenes (Rosenbach)
Migula). Also include here A. rhenanus CMigula), A. candicans (Flugge), and
A. canescens (Migula).

GENERAL SYSTEMATIC BACTERIOLOGY 173

This genus has been considered invalid by Winslow, Rothberg, and Parsons
(J. Bact., V. 5, no. 2, 1920, p. 161). The tj-pe species A. pyogenes together with
Staphylococcus epidermidis albus (Welch) Gordon, and Albococcus epidermidis
the Winslows, becomes Staphylococcus epidermidis.

If the white pus cocci and related forms are to be grouped together
as a genus, the generic name Albococcus Winslow with the type species
Albococcus albus (Ros.) would appear to be valid. If they are not
sufficiently distinct to warrant generic recognition, they should be grouped
with the golden forms in the genus Staphylococcus Rosenbach.

Alcaligenes. A generic name proposed by Castellani and Chalmers.
The first reference is 1919, p. 936. It is here cited, however, as 1918.
The diagnosis given is as follows :

Definition: Ebertheae which do not ferment glucose or lactose, and are char-
acterized by their general lack of fermentative power and by actually increasing
the alkalinity of the media. Milk is not clotted, and is rendered alkaline.

Type: Alcaligenes faecalis (Petruschky, 1896), emendavit Castellani and
Chalmers, 1918.

Here also comes Alcaligenes vivax (Archibald, 1918), which was obtained from
the blood of a case of enteroidea in the Anglo-Egj'ptian Sudan, produced acidity
in galactose and mannitol and was characterized by its marked motility.

The genus was also later discussed (1920, p. 604) with two species
described.

Bergy et al. (1923, p. 233) included this as the sixth genus of the tribe
Bactereae with the description "Motile or non-motile rods, generally
occurring in the intestinal canal of normal animals. Do not form
acetyl-methyl carbinol. Do not ferment any of the carbohydrates."

Alkalibacteriaceae. A family of bacteria named by Orla-
Jensen (1909, p. 313) belonging to the order Peritrichinae Orla-Jensen.
It contains three genera, Liquidobacierium Orla-Jensen, Bacillus Cohn,
Urobacillus IMiguel. It includes those bacterial genera characterized by
the production of a decided alkaHne reaction in media as a result largely
of the development of ammonia. The bacteria are neither obligate
anaerobes or microaerophiles. The name of this family does not conform
to Article 21 of the botanical code because it is not designated "by the
name of one of its genera or ancient generic names wdth the ending
aceae. " It would appear therefore not to be tenable.

Alkaligenes. A variant spelling of Alcaligenes (q.v.). It was used
by Castellani and Chalmers (1919, pp. 1405, 1408, 1409) in referring
to their genus Alcaligenes described earHer in the same volume. It is
also used by Evans (1923, p. 1945).

174 GENERAL SYSTEMATIC BACTERIOLOGY

Allococcaceae. A subfamily of bacteria belonging to the family
Coccaceae described by Fischer (1897) (1903, p. 59). The subfamily
is regarded as made up of two genera, Micrococcus Cohn and Planococcus
Migula. It contains those cocci in which the planes of fission have no
definite sequence, and there are no pronounced colonies or growth
forms. The cells are isolated, in short chains or irregular clusters.

The ending of the name of this subfamily, if used, should be oideae
rather than aceae in conformity with Article 23 of the International
Code. The code specifically states: "Names of subfamihes {suh-
familicB) are taken from the name of one of the genera in the group
with the ending oideae." As a subfamily name Allococcaceae would
therefore appear not to be tenable for this reason and because not
derived from the name of one of the constitutent genera.

Amoebobacter. A genus of the sulphur bacteria described by Wino-
gradsky (1888, p. 71). He says,

. . . . findet man eine Familie von so dicht zusammengepressten Zellen,
dass man die einzelnen Zellen fast gar nicht unterscheidet, und die ganze Gruppe
fast homogen erscheint. Die Farbung ist zart rosenroth: hier und da finden
sich wenige Schwefelkornchen. Um die Zellenmassen sieht man eine Hulle,
welche aus zwei Schichten besteht; eine immere schwach lichtbrechende und
eine aussere stark lichtbrechende deutlich doppelt contourirte Schicht. Stellt
man eine solch encystierte Familie ein, so sieht man etwa nach 4 Tagen dans
die Cyste gesprengt wird und ihr nunmehr deutlich aus Coccen bestehender
Inhalt ausserst langsam herauszukriechen beginnt. Der Austritt dauert manch-
mal 1-2 Tage. Es bliebt eine leere Cyst zuriick, welche sich noch lange unver-

andert erhalt Der Gestaltwechsel der Amoebobacterfamilien hat

seinen Grund darin, dass sowohl die einzelnen Zellen innerhalb der Familie,
als die Familien als ganze beweglich sind.

Three species are described, Amoebobacter roseus, A. granula and
A. bacillosus. In the first the cells are spherical 2.8 to 3.4/i in diameter,
or elongate to 6^. In the second the cells are very minute, scarcely
0.5^1, and in the last the cells are rod shaped, 2 to 4/x long and 1.7/i
thick.

The genus was next recognized by De Toni and Trevisan (1889,
p. 1043) as the only genus of the tribe Amoebobacterieae Trevisan.
They give the following definition:

Cocci globes vel ovoideo-ellipsoidei, densissime in familias primitus adparenter
fere homogenes, amoeboideomobiles cumulati cysti debus bistratosis circum-
cincti interiori stratu parum refringente, exteriori valde refrigente cito delabent-
ibus. Cocci demum liberi mobiles. Coccorum divisio in unam directionem.

GENERAL SYSTEMATIC BACTERIOLOGY 175

Winogradsky's three species are recognized.

An adequate study of this group since the monograph of Winogradsky
does not seem to have been made, although the genus Amoebobader
Winogradsky has been accepted by many subsequent authors. This
genus was included by Migula (1900, p. 1045) in the subfamily Amoebo-
baderiaceae, together with the genera Thiodidyon, Thiothece and Thio-
polycoccus. IVIigula (1904, p. 146) gave the following generic diagnosis:
"Zellen zu Famihen vereinigt, nach einen Richtung des Raumes sich
teilend; Familien amoeboid bewegUch, Zellen durch Plasmafaden
verbunden. "

Erwin F. Smith (1905, p. 163) hkewise places the genus in the family
Amoebobaderiaceae, and with the following description:

Cells connected by plasma threads. Families amoeboid motile. The cell
families slowly change form, the cells drawing together into a heap or spreading
out widely, thus bringing about a change in the shape of the whole family. In
a resting condition a common gelatin is extruded, the surface of which becomes
a firm membrane.

In several descriptions, the connecting threads are designated as
protoplasmic, apparently without sufficient justification. For example,
Frost (1911, p. 61) in a tabulation of Migula's classification states:

The cells are united into colonies, and after division in one direction of space
remain attached together by threads of protoplasm. The colonies possess
amoeboid motility. The cells change form by contraction and the spreading out
of the protoplasm.

Buchanan (1918, p. 469) designated the first species described by
Winogradsky, A moe6o6ader roseus, as the type. His description follows :

Cells connected by plasma threads. Families amoeboid motile. The cell
families slowly change form, the cells drawing together into a heap or spread-
ing out widely, thus bringing about a change in the shape of the whole family.
In a resting condition a common gelatin is extruded, the surface becomes a
firm membrane.

Enlows (1920, p. 14) gives the following characterization:

Cells divide in one direction of space, usuallj' round, and united into families
by means of plasma threads. Families have amoeboid motion. In the resting
state the extruded gelatin becomes stiffened, forming a firm 2-layered mem-
brane. Sulfur granules here and there. Cell masses a delicate rose red.

Type species (subsequent designation by Buchanan (J. Bact., v. 3, no. 5,
1918, p. 469)). Amoebobacter roseus Winogradsky. Cells spherical, 2.8 to 3.4/i
in diameter. Winogradsky also includes here A. bacillosus (rodlike cells 2 to

176 GENERAL SYSTEMATIC BACTERIOLOGY

4/t long by 1.7m), and A. granula (cells spherical, exceedingly small — scarcely
0.5m in diameter).

Bergey et al. (1923, p. 398) followed Buchanan.

Orla-Jensen (1909, p. 334) proposed that Amoebohacter be replaced
by a new term Amoehomonas.

Apparently no author has studied the organisms of this genus since
Winogradsky's original description.

Amoebobactereae. A variant spelling of Amoehobaderieae used
by Bergey et al. (1923, p. 398) for the fourth tribe of the subfamily
Chromatioideae with the description: "Sulphur bacteria in which the
cells are united into families. Cell division occurring only in one direc-
tion of space."

One genus only, Amoebobacter is included.

Amoebobacteriaceae. A subfamily of the family Rhodobaderia-
ceae of the sulphur bacteria established by Migula (1900, p. 1045)
to contain the genera Amoebobader, Thiodidyon, Thiothece, and Thio-
polycoccus.

This subfamily is characterized by having the cells united into fam-
ilies, cell division occurring in one direction of space. It has generally
been recognized by subsequent authors dealing with this group, as
Migula (1904, p. 146), Erwin F. Smith (1905, p. 163), Frost (1911, p. 61).

Article 23 of the International Rules for Botanical Nomenclature
would require the change of the subfamily name to Amoebobaderioideae.

Amoebobacterieae. A subtribe of the tribe Ascococceae Trevisan
(1889, p. 1043) established by Trevisan, to include the single genus
Amoebobader. The diagnosis given is "Cocci in muco matricali in
series filamentosas laze conjundi. Cystides universales tenuissimae,
cito dilabentes. Cystides speciales nullae.''

The International Rules of Botanical Nomenclature (Article 23)
would require the change of this name if used for designation of a
subtribe to Amoebobaderinae.

The same name was used by Buchanan (1918, p. 469) to designate a
tribe with the following diagnosis " Sulphur bacteria in which the cells
are united into families. Cell division occurring only in one direction
of space. " Four genera were included Amoebobacter, Thiodidyon, Thio-
thece and Thiopoly coccus. Bergey et al. (1923, p. 398) used the spelling
Amoebobactereae g.v.

Amoebomonas. A name proposed by Orla-Jensen (1909, p. 334) to
replace the generic name Amoebobacter, Winogradsky of the Rhodo-

GENERAL SYSTEMATIC BACTERIOLOGY 177

hadenaceae. It is a synonym, and probably invalid as a generic
designation. No species were designated.

Amphitricha. A designation suggested by Messea according to
Kruse for those motile bacteria with a flagellum at each end of the cell.
It is the first group of the Trichobaderia q.v.

Amylobacter. A casual name used by Trecul (1865, p. 435) for
certain rods found between the cells of decajdng plant tissues. He
said

Malgr6 la variety des formes de ces petits vegetaux, au plutot a cause de cette
variety meme puisqui I'on passe d'une forme k I'autre par toutes les gradations;
en raison aussi de I'amidon qu'ils contiennent, et pour rappeler la resemblance
des formes cylindroides avec les Bacteries, je crois utile de les reunir sous le
nom d' Amylobacter. Si on voulait les diviser d'aprds les formes les plus dis-
parates, on pourrait 6 tablir troir sous genres; 1, "V Urocephalum qui compren-
drait les formes en tetard; 2, V Amylobacter vrai, auquel serarent attribuees les
formes cylindrace^s; 3, le Clostridium, qui refermerait les formes en fuseau.''

This author gave no specific names. What was later regarded as
the same organism was named Bacillus amylobader by Van Tieghem
(1879, p. 25).

Duclaux (1895, p. 813) revived the name, describing two species,
Amylobader butylicus, and Amylobader ethylicus.

Ce sont partout des bacilles dont la largeur et la longueur varient avec le
milieu de culture, cylindriques lorsqu'ils sont jeunes, se renflant plus ou moins
quand ils vieillissent, en un point oil apparait la spore. Chez la plupart d'entre
eux, de meme du reste qu'avec des bacilles qui ne consomment ni amidon ni
cellulose, la formation de les spore est precedee d'une p6riode oti une partie du
protoplasme du bacille se colore par I'iode.

He notes that Beijerinck had previously suggested Granulobader
for this type of organism.

The genus should be ascribed to Duclaux. A. butylicus is the type.
Amylobader is listed as a synonym of Clostridium by Prazmowski
(1880, p. 23) and by De Toni and Trevisan (1889, p. 1002). It is re-
jected by Erwin F. Smith (1905, p. 174).

The use by Trecul of the name Amylobader does not entitle it to
generic recognition because it was not coupled with the name of any
particular species in the form of a binomial. It existed therefore,
simply as a casual name until its use by Duclaux. In the meantime,
however, the genus Clostridium (q.v.) had been created for such types
of bacteria. As a generic designation it should probably be written

178 GENERAL SYSTEMATIC BACTERIOLOGY

Aniylohacter Duclaux. It is a synonym of Clostridium, and Granu-
lobacter at least in part.

Amylobakter. A German spelling of Amylobader. A casual name.
It has been used among others by Schattenfroh and Grassberger
(1899, p. 700). It is not a valid spelling of the generic name.

Aphaneroglia. A generic name proposed for the single genus of
the first order Protobacteries by Maggi (1886, p. 81). One species,
A, apuae potabilis is listed, but without description.

Aplanobacter. A generic name proposed for non-motile rods by
Erwin F. Smith (1905, p. 171). The diagnosis given by Smith is as
follows :

An unattached, non-motile, rod-shaped organism, destitute of chlorophyll
and multiplying by fission, sometimes forming threads of considerable length.
The type of the genus, in the family Bacteriaceae, is that organism causing
anthrax and most commonly known in literature as Bacillus anthracis Cohn.

The generic names Bacillus Cohn and Bacteridium Davaine have
both been apphed to this type species. The type of the genus Bacillus
Cohn is generally accepted as Bacillus subtilis Cohn. The essential
morphological difference between B. subtilis and B. anthracis is the
possession of peritrichous flagella by the former, and their absence
in the latter. Smith contends that lack of motility is a characteristic
which warrants the separation of the anthrax organism from Bacillus.
Evidence is continually accumulating to show that generic separations
among the bacteria solely on the basis of motility lead to a violent
disarrangement of natural groupings. Granting, however, that another
generic name should be found, Davaine's genus Bacteridium would
appear to be tenable. It was founded upon the B. anthracis and created
because of the lack of motility of this form. Smith argues that the
name Bacteridium (q.v.) is preoccupied in botany. However, the names
previously used (see discussion of Bacteridium) have been spelled
Bactridium. Smith regards this as the same word, making Bacteridium
untenable. As noted elsewhere, a strict interpretation of the rules of
the International Code would indicate that the difference in spelling
is sufficient to make the generic name Bacteridium valid. It should
also be noted that the generic name Pollendera Trevisan (1885) has
priority over Aplanobacter.

Migula has defined the genus Bacterium (q.v.) to include the non-
motile rods. As noted elsewhere, this use of the term Bacterium is
scarcely justified, it probably should not be used in this group.

GENERAL SYSTEMATIC BACTERIOLOGY 179

It would seem that the generic name Aplanohacter Smith must be
regarded as a synonjTii of Bacteridium Davaine, and hence invalid
unless it can be shown that for some reason the latter name as well
as Pollendera are not tenable.

Arloingillus. A genus of anaerobic spore bearing bacteria pro-
posed by Heller (1922, p. 21). Her description follows:

Clostridioideae that attack sugars with considerable energy but have a some-
what restricted action on proteins. Liquefy gelatin but do not produce H2S
demonstrable by a lead-acetate-paper test in blood broth. In meat medium
produce gas and a pink coloration that soon fades. Autoagglutinate readily.
Clot milk if blood is present. Do not digest serum or egg. Vegetative forms
are small Gram-negative rods with even staining; forms about to sporulate are
uneven in staining reaction, often far larger than vegetative rods, citron or
spindle shaped; orgonts (see Heller), show marked tendency to store up granu-
lose. Spores oval, vary greatly in length. Bacilli do not form long chains in
the liver of animals. Colonies in deep agar lenticular, sometimes showing con-
centric formation, or compound lenticular. Colonies vary considerably ac-
cording to species. T\qoically toxic tissue invaders which produce marked
haemolysis. Pathogenic for guinea-pigs, cattle and sheep.

Type species A. C/iawt'oei {Bacterium Chauvoei Arloing, Cornevin, and Thomas)
as described in a future paper.

This genus contains several species which will be discussed. These organisms
show some similarity to those of the genus Clostridium.

The B. enteritidis-sporogenes Klein, as described by von Hibler (1908) should
probably be included in the genus. The only character which is markedly
different from that of the genus is the energetic fermentation of milk shown by
von Hibler's bacillus IV.

Arthrobacillus. A genus of bacteria proposed by Fischer (1895,
p. 136) to include the non-motile rod-shaped organisms which pro-
duce arthrospores. No type was designated.

Arthrobacter. A generic name proposed by Fischer (1895, p. 141)
to include all non-fiagellate rod-shaped bacteria which produce
arthrospores. No species are named, hence the genus is invalid. He
says "Vorlaufig kann keine Art mit Sicherheit hierhergestellt werden,
vielleicht wiirde das Bacterium Ureae hierhergehoren. " He apparently
ascribes the name to De Bary as he writes Arthrobacter (De Bary).
Fischer (1903) himself later abandoned the designation. It is listed
as invalid by Erwin F. Smith (1905, p. 174).

Arthrobacteriaceen. A "Gattung" proposed by Hueppe (1886,
p. 145) to include the rod shaped bacteria which produce arthrospores
or at least do not form endospores. The " Untergattungen " Arthro-
hakterium {Bakterium s. str.) and Spirulina (Proteus) are included.
Evidently this should be regarded as a casual family name.

180 GENERAL SYSTEMATIC BACTERIOLOGY

Arthrobacterium. A name proposed by De Bary (1884) to in-
clude rod-shaped bacteria which produce arthrospores. No species
were described. The genus was also mentioned by Hueppe (1886)
and was included in his classification of bacteria. De Toni and Trevi-
san (1889, p. 1054) give Arthrobacterium De Bary (1887) as a synonym
of Streptococcus. As stated by Vuillemin (1913, p. 520) this genus has
not been preserved or used because it was founded upon the false assump-
tion of arthrospore formation.

Enlows (1920, p. 15) states:

According to Comp. Morph. and Biol. Fungi, Mycetozoa and Bact., Auth.
Eng. rev. trans, by Garnsey, Oxford, 1887, pp. 454 and 468. This genus is pro-
posed for that group of the genus Bacterium in which no endogenous spore-
formation occurs. "To denote the species which constitute the genus Bacterium
of authors, I use partly the generic name Bacillus .... and partly the
name Arthrobacterium. Single members may simply separate from their con-
nections with others, and under suitable conditions become the initial members
of new combinations; they have therefore claim to the name spore. In other
respects there is no general characteristic distinction between them and the purely
vegetative members.

Species. Bacterium zopfii Kurth, Bact merismopoedioides, Bact. aceti, and
Bact. pastorianum Hansen.

Maggi (1886, p. 84) gives Arthrobacterium aceti De Bary as a synonym
of Bacterium aceti Zopf.

It is doubtful whether the rather casual use by De Bary is sufficient
to validate the genus. Apparently no type has been designated.

Arthrobactridium. A genus proposed by Fischer (1895, p. 140)
to include those rod-shaped bacteria with diffuse flagella which pro-
duce arthrospores. The genus was later abandoned by Fischer (1903)
as based upon a false interpretation of morphology. It is also re-
jected by Erwin F. Smith (1905, p. 174). The genus is not tenable
because no species have been definitely assigned to it.

Arthrobactrillum. A generic name proposed by Fischer (1895,
p. 139) to include those rod-shaped bacteria which are motile by means
of a tuft of polar flagella, and which reproduce by means of arthrospores.
The name is invalid. It rests upon a mistaken interpretation of
morphology and has no described species. It was later abandoned by
Fischer (1903) himself as untenable. It is also rejected by Erwin F.
Smith (1905, p. 174).

Arthrobactrinium. A generic name proposed by Fischer (1895,
p. 139) to include rod-shaped bacteria having one polar flagellum
and producing arthrospores. This generic name has never come into

GENERAL SYSTEMATIC BACTERIOLOGY 181

general use. It is founded on a misconception of bacterial morphology,
has no named species, and has been abandoned by its author (1903).
It should be considered as invalid. It is rejected by Erwin F. Smith
(1905, p. 174).

Arthrobakteriaceen. A variant of Arthrobaderiaceen. A name used
by Hueppe, (1886, p. 145) for a "Gattung" including the rod-shaped
bacteria which produce arthrospores or at least which do not produce
endospores. The " Untergattungen " included are Arthrobakteriurn
(Bakterium s. str.) and Spirulina (Proteus). The name is not Latin
in form. It must be regarded as untenable.

Arthrobakterium. A spelling of Arthrobacterium De Bary (q.v.)
used by Hueppe (1886, p. 145) to designate an " Untergattung " of the
"Gattung" "Arthrobakteriaceen/' It is also given di'S, Bakterium sensu
strictu. It includes those straight rod shaped organisms which pro-
duce arthrospores, or at least do not produce endospores.

Arthrokokkaceen. A name used by Hueppe (1886, p. 144)
for a "Gattung" of bacteria with spherical cells which produce arthro-
spores or whose method of spore production is unknown. The follow-
ing "Untergattungen" are included: Arthro-Streptokokkus, Leuconostoc,
Merista, Sarcina, Mikrokokkus, Askokokkus. It may be regarded as
invahd.

Arthromitus. A generic name proposed by Leidy (1849, p. 227)
for two organisms found in the rectum of Julus. These he named
Arthromitus cristatus and A. nitidus.

The following is the description given by Leidy to the genus and
to the first species described:

Filaments always simple, cylindric, articulated, without ramuli, attached
by means of a nuclear bodj', and with no evidence of interior structure.

Arthromitus cristatus. Filaments delicate, straight or inflected, growing in
tufts usually of moderate density, from minute, attached, yellowish rounded or
oval nuclear bodies. Articuli short, cylindric, uniform, measuring § 0*9 o^ inch
in length by "r^^^o^o^ in breadth, with no traces of interior structure.

Length -^\^ to :fV inch, breadth y^Vo^T inch.

Habitat. Same as Cladophijtum comatum, but rarely growing in such dense
tufts.

Later (1852, p. 35) he described Arthromitus nitidus. This species
is described as follows:

Filaments very long, hyaline, grows usually in twos or fours, pointed at the
origin, rounded at the termination. Articuli very distinct, length equal to the
breadth of the filament. Sporuli formed within the articuli solitary, usually
oblique, oval, amorphous.

182 GENERAL SYSTEMATIC BACTERIOLOGY

Length 1 lineby-g otT) inch broad. Spores yij^ inch long, by i-g-i-jyi^ inch broad.

Habitat. Grows in considerable quantity with a profusion of young of En-
terobryus elegans from the mucous membrane of the posterior portion of the
rectum of Julus marginatus.

Remarks. Since I established the genus Arthromitus I have observed the
formation of its sporuli. These originate in the amorphous matter of the ar-
ticuli, apparently by a vory gradual aggregation and condensation of the con-
tents. They are always single, and usually lie oblique, and frequently alternate
with each other in this position in the different articuli. When they first appear
they are larger than when fully formed, are frequently bent, or clavate in form,
and very indistinct, but as they ripen they become more regular, oval, distinct,
and quite refractile of light. Usually they are observed at the extremity of the
filaments only, but frequently they are found existing in the whole length of
the latter.

A species of Arthromitus, and also of Cladophytum is found in the intestine
of Polydesmus virginiensis.

Robin (1853, p. 359) gives the following generic and specific
description :

Filaments toujours simples, cylindriques, articules, sans ramifications, fixes
au moyen d'un corps nucleaire, sans structure bien definie.

Arthromitus cristatus, Leidy. Filaments fins, croissant en touffes medio-
crement e'paisses, sur de petits corps arrondis, fixes et jaunatres; articles courts,
cylindriques, uniformes, ayant O'^^ 002 ( 9 ^^q de pouce) de long etO-^^jOOl (t^.^uv
de pouce) de large, sans structure int^rieure.

Ce vegetal offre une longueur qui varie entre 0'"'",065 et 0'°'",543 (^^^et^V
de pouce), et une largeur de 0'""',001 (ysVo de pouce). II se trouve dans
les memes points que le Cladophytum comatum, mais rarement en touffes aussi
epaisses.

Arthromitus nitidus, Leidy. Filaments tres longs, hyalius. croissant au
nombre de deux ou quatre, amincis h I'origine, arrondis vers leur terminaison;
articles tres distincts, ^ longueur egale a la largeur du filament, et renfermant
des sporules generalement ovales, amorphes et isoi6e?.

Ce vegetal a environ 2'°™,13 (1 ligne anglaise de long), surO°"°,005 (^^^o^ de
pouce) de largeur. Spores, 0°"",003 (ttVt dc pouce) de long, ou O'»'",002 x-^.i^fr
de largeur.

II croit en grande quantity avec VEnterobryus elegans dans la muqueuse de
I'extr^mite du rectum du lulus marginatus. Une espece d' Arthromitus se trouve
aussi dans I'intestin du Polydesmus virginiensis.

Les sporules des Arthromitus se forment par condensation de la substance
amorphe qui remplit les articles. lis sont toujours isoles, ordinairement places
obliquement. Quand ils commencent a se former, ils sont plus grands que
lorsqu'ils ont acquis tout leur developpement, un peu recourbes et tres peu
distincts; mais en murissant ils deviennent plus r^guliers, ovales, tres nets, et
r^fractant bien la muniere. Quelquefois on ne les trouve qu'^ I'extremit^ des
filaments, mais souvent il en existe dans toute leur longueur.

GENERAL SYSTEMATIC BACTERIOLOGY 183

Collin (1913, p. 63) revived the generic name as a suitable designa-
tion for an organism from the alimentary tract of the frog. The species
Arthromitus hatrachorum is described as follows:

Son thalle filamenteux, non rameux, k croissance inddfinie ,k contenu gran-
uleux partag6 en articles d'environ 3,5u de large sur 2 ^ 3/x de hauteur, circulaires
en coupe transverse, rappelle d'assez pres le port de certaines Oscillari6es mais
il est incolore. De place en place, et sur certains thalles seulement, des cel-
lules plus ^paissies, k contenu tres colorable font quelque peu saillie sur I'aligne-
ment des autres apr^s la fixation; on voit souvent, de chaque cot6, des cellules
claires d^g^nerdes. Je pense qu'il s'agit la peut-^tre d'^lements vieillis ou
morts, tels que ceux qu'on observe chez beaucoup de Cyanophycees (les Scyto-
nema par exemple), <51^ments qui pourraient se trouver liberes par la rupture
du thalle. La sporulation a lieu par voir endogene, avec une spore pour chaque
cellule et d'une maniere toute sporadique pour les cellules d'un thalle donn6;
la spore est arrondie, circulaire en coupe transverse, mais tr^s nettement ellip-
soide quand on I'apercoit de profil. EUe est situee k I'int^rieur de la cellule
avec une forte obliquity. Les ebauches sporales, d'abord spheriques et trfes
petites, puis plus volumineuses, se colorent intensement par les m6thodes k
froid (h^matoxyline ferrique par exemple), tandis au'^ maturite complete, elles
ne sont plus p^n^trables qu'^ chaud, comme chez les autres Bact^ries. Rectum
des tetards d'Alyte en compagnie de Bacillus camptospora et de Spirillum pro-
eclarum; trouv6 aussi (ou une forme tres voisine) dans I'intestin post6rieur
des larves de Bufo calamita Laur. k Viarmes (Seine-et-Oise).

Chatton and Perard (1913, p. 1160) conclude that the Hygrocrocis
intestinalis of Valentin and the Arthrornitus cristatus of Leidy belong
to the same genus, and on grounds of priority they select Hygrocrocis.
They say:

Dans des preparations de contenu intestinal de termites nous avons retrouv6
les Arthromitus de Leidy, et M. A. Borrel nous a montre chez des Blattes des
schizophytes que nous identifions a {'Hygrocrocis intestinalis de Valentin. II
nous semble d'ailleurs que ces formes sont gen^riquement identiques.

Ce sont de longs filaments k compartiments subegaux, cubiques, a croissance
indefinie, immobiles, et qui au surplus sont, d'apres Leidy, fixes a la paroi in-
testinale par bouquets sur une sorte de pied commun globuleux. II y a dans
les regions sporul^es de ces filaments une endospore par cellule et ces cellules
sporigenes ne sont point hj^pertrophi^es. {See Hygrocrocis.)

Apparently Arthromitus is a valid generic designation.
Arthrospirobacterium. Enlows (1920, p. 16) states:

This genus has been ascribed to Hueppe. In his "Die Formen d. Bakt.,"
Wiesbaden, 1885, p. 146, where he classifies the bacteria, he gives as "Gattung"
III, Arthro-Spirobakteriaceen. The vegetative cells are screw-like rods. No
endogenous spores. Arthrospores. He places Spirochaeta as a subgenus of
this.

184 GENERAL SYSTEMATIC BACTERIOLOGY

The ascription noted by Enlows has not been found.
Artho-Spirobacterium. Enlows (1920, p. 88) states:

Arthro-Spirobacterium : Klebs, 1887.

Die Allg. Path., Jena, 1887, p. 88. In a resume of Hueppe's classification,
Klebs gives this spelling, and cites the 1881 edition of Hueppe's Die Formen d.
Bakt.

Arthrospirobakteriaceen. A name used by Hueppe (1896, p. 146)
to designate a "Gattung" of bacteria in which the cells are spiral,
and which produce arthrospores, or at least do not produce endospores.
One " Untergattung " only, Spirochaeta, is included. The name is
evidently invalid, or at most, a casual family designation.

Arthrostreptococcus. A variant (in proper form) of Arthro-
StreptokokkiLS q.v.

Arthro-Streptokokkus. A sub-generic name proposed by Hueppe
(1886, p. 144) to include those bacteria with spherical cells, occurring
in chains in indefinite zoogloea, and without endospores. It is based
upon a misconception of morphology, it is not spelled as a Latin word,
no species are definitely assigned to it, and it is essentially synonjnnous
with Streptococcus.

Ascobacillus. Apparently first introduced as a casual name by
Edington (1887, p. 1265) for an organism found in the blood of a
patient with scarlet fever. De Toni and Trevisan (1889, p. 1034) under
"species quod genus dubia" give Edington's "ascobacillus of Scarlet
Fever" as a synon^nn of Klebsiella Edingtoni Trevisan. The follow-
ing description is given.

Baculis cylindraceis, tenuibus, 0.8/t longis, 0.2/Lt latis. Sporae pluries centum
in capsulis, quam baculis multo amplioribus, lucanicaeformibus contentae.
Hab. in squamis et sanguine hominum scarlatina laborantium. In culturis
gelatinamo lente liquefacit; coloniae flavae.

Enlows (1920, p. 16) says

Small rods, 0.8iu long by 0.2^ broad, often dumb-bell shaped, made up of long
ovoid spheres. Spores are contained in large sausage-shaped capsules many
hundred times larger than the bacilli themselves. Found in the blood of a
patient dying of scarlet fever.

As a generic designation Ascobacillus was first used by Unna and
Tommasoli (1889). The name first appeared (p. 15) as Ascobacillus
citreus in a list of organisms isolated from the skin. Later (p. 60)
the organism is more adequately described.

GENERAL SYSTEMATIC BACTERIOLOGY 185

The organism is a straight or somewhat bent rod, l.Sju by O.Spi, single or in
pairs or bundles, motile, spores unknown. On gelatin the growth is very slow,
in two weeks the superficial colonies are opaque yellow points, the deep colonies
scarcely yellow. Under low magnification the latter are gray yellow, opaque.
The organism is aerobic, does not produce gas and forms a citron yellow pig-
ment.

Migula (1900, p. 842) termed this organism Bacillus citreus.

Moreno (1901, p. 112) described an Ascobacillus aquatilis. Mac4
(1913, p. 586) regards Ascobacillus as a synonym of Ascohacterium q.v.
making Ascobacillus citreus a synonjon of Ascobacterium luteum Babes.
Mac6 also includes as a synonym the Ascobacillus sacchari Greig-Smith
(1903).

Enlows states (1920, p. 16: for the Unna type):

Straight or bent bacilli, 1 to 3u by 0.3/u, single or in twos, grouped or in bundles.
Masses taken from agar present the appearance of Ascococmis billrothii Cohn.
In the interior of these masses the bacilli are nonmotile, but at the periphery
a whirling motion may be observed.

Type species (monotj^py). A. citreus. Produces a citron j-ellow color on
media. Liquefies gelatin.

If the organism described by Unna and Tommasoli is worthy of
recognition as a generic type, the name Ascobacillus would probably be
valid. It is possible that it might be used as a generic name for yellow
pigment forming rods if these should be grouped together, as has been
done in Flavobacterium q.v. Otherwise Ascobacillus may be regarded
as a synonym and not tenable,

Ascobacteria. A name (form genus) suggested by Billroth (1874)
but with no designation of species.

It was proposed as a generic name by Van Tieghem (1880, p. 151).
Under the grouping of colonies provided with a membrane, he states
that the types with cylindrical cells may be combined into the genus
Ascobacteria, which he regarded as an encapsulated Polybacteria. One
species was described, Ascobacteria ulvina Van Tieghem. It developed
on the surface of water in which leguminous seeds (lupine) were rot-
ting. It occurred in granular, polyhedral masses, each enveloped in
a thick cartilaginous membrane, in a layer like the alga Ulva. Cells
numerous small rods embedded in a common gelatin. After the mass
reaches a certain size, it splits, while the gelatinous membrane is
continued over the two daughter masses.

186 GENERAL SYSTEMATIC BACTERIOLOGY

Later Van Tieghem (1884, p. 1114) evidently regarded this as a
form genus. It was also recognized by Billet (1880, p. 24).

Apparently the genus was validly described, with type species
Ascobacteria ulvina Van Tieghem. However, the species is so poorly
characterized that its identification is questionable.

Ascobacterium. A generic name used by Babes (1890, p. 155) in
his description of Ascohacterium luteum. This organism is mentioned
as common in the air of the laboratory at Buda Pesth and in the water
of the Dumbivotza. It forms very pronounced transparent, yellowish
colonies on gelatin. The cells are rod-shaped, united in greater or
less numbers by a large gelatinous or mucous capsule.

Mace (1897, p. 962) believes that there may be a relationship ex-
isting between this form and that described under the name Asco-
coccus.

Mace (1913, p. 586) states

Les elements en bdtonnets, ventables Bacilles, sont reunis, en nombre plus
ou moins considerdble, dans une grande capsule ovalaire, gelatineuse ou mu-
quese. Le nom d'Ascobacillus doit etre consider^ comme synonyme et serait
certainement a preferer, si Ton etait tout a fait fix e sur I'individualite de ces
types microbiens; on peut conserver le terme Ascobacterium comme provisoire.
II y a peut-etre des rapports a etablir entre ce type et ceux d^crits sous le nom
d'Ascococcus.

He describes Ascohacterium luteum Babes and Ascobacterium aqua-
tile (Moreno) Mace (Ascobacillus aguatilis Moreno).

It would seem that this genus has been validly described, with
type species Ascobacterium luteum Babes. It is possible that it should
be regarded as a synonym of Ascobacillus, q.v.

Ascococceae. A name of a tribe of cocci of the subfamily Cocco-
genae Trevisan proposed by Trevisan (1889, p. 1037). It contains the
sub-tribe Euascococceae Trev. with the genera Lamprocystis Schroeter,
Ascococcus Cohn, Bollingera Trevisan, Cenomesia Trevisan, Thiocystis
Winogradsky, Thiothece Winogradsky, Leucocystis Schroeter, the sub-
tribe Gaffkyeae Trevisan with the genera Chlamydatomus Trevisan and
Gaffkya Trevisan and the subtribe Amoebohacterieae Trevisan, with
the single genus Amoebobacter Winogradsky.

It is characterized as follows: "Cocci in familias tegumentis vesic-
aeformibus gelatinosis (cystidibus) obductae consociati."

The name has apparently been used by no other author.

Ascococcos. A form genus proposed by Billroth (1874, p. 13).
It was intended to include those growth forms of the poljmiorphic

GENERAL SYSTEMATIC BACTERIOLOGY 187

Coccdbacteria septica (q.v.) in which the cells are spherical and em-
bedded in relatively dense zoogloeal masses, the masses being well
limited, usually oval and distinct. To one particular form the binomial
Ascococcos parvus (p. 98) was given. This is insufficiently described and
cannot now be recognized.

The generic designation Ascococcos Billroth should be regarded as
invalid for the following reasons:

1. The name Ascococcos uses the Greek termination os instead of
the Latin us. Article 7 of the Botanical Code specifically states :

Scientific names are in Latin for all groups. When taken from another
language, a Latin termination is given them, except in cases sanctioned by
custom.

2. The name was never proposed by Billroth as a valid generic
designation but as a growth form only.

3. The only species (A. parvus) assigned to the genus was inadequately
described.

This name was changed to Ascococcus by Cohn (1875, p. 147) who
writes "Billroth schreibt Ascococcos, wie Micrococcos, etc; der Gebrauch
sanctionirt jedoch nur die lateinischen Endungen selbst bei Namen
griechischen Stammes (Lois de la nomenclature botanique Article
66)." The generic name therefore, in spite of Cohn's statement "Asco-
coccus Billroth char, emend." should read Ascococcus Cohn" (q.v.),

Ascococcus. The form genus Ascococcos (q.v.) was created by
Billroth (1874, p. 13) for a growth form of his Coccohacteria septica
in which the spherical cells are embedded in gelatin or slime. This
is not tenable as a generic designation. Cohn (1875, p. 154) published
the genus name "Ascococcus Billroth char, emend." This should be
written Ascococcus Cohn.

The generic description given by Cohn is :

Cellulae achromaticae globosae densissime consociatae in familias tubercu-
losas globosas vel ovales irregulariter lobatas, lobis in lobules minores sectis
capsula globosa vel ovali gelatinoso-cartilaginea crassissima circumdatas, in
membranam moUem facili secendentem floccosam aggregatas.

One species was described, Ascococcus Billrothii, from a zoogloea
mass developing spontaneously in a culture medium of ammonium
tartrate. The specific diagnosis is

Familiae tuberculosae 20-160/* capsula ad 15/1 crassae. In solutione ammoni
tartarici acidi a6ro lavata vel butyrico praeditam formanten observavi Mart

188 GENERAL SYSTEMATIC BACTERIOLOGY

1874. Haud scio citrum eandem an aflfinem speciem ill. Billroth in aqua carnis
foetida detexerit.

Cohn believed that the organism which he described was the same
as that of BiUroth, hence the choice of name. He also concluded
that the Ascococcos parvus of Billroth was not a true Ascoccocus in
the sense of Billroth's original description.

Cienkowski (1878, p. 12) described an organism responsible for a
gummy or viscous fermentation of syrups in sugar factories. He re-
garded it as confonning to Cohn's conception of Ascococcus and named
it A. mesenteroides. A study of the same organism was made by Van
Tieghem (1878, p. 198). He concluded that this form was distinct
from Ascococcus Cohn and made it the type of the genus Leuconostoc.
He called attention to the points of difference between the two genera.
In Ascococcus the cells are spherical, very small, and grouped in great
numbers to form globular or avoid families which are lobed more or
less irregularly. The cells are closely united, separated only by a small
amount of gelatinous material ; each family is surrounded by a cartilag-
inous envelope. In Leuconostoc the cells are arranged in bent chains
separated from each other by a large amount of gelatinous material,
the gelatin on the exterior not being thicker than that between the
chains. The Ascococcus of Cohn grew in ammonium tartrate solution,
the Leuconostoc in sugar and rendered the solution decidedly acid.
He places the genus Leuconostoc among the Nematogenae in Cohn's
classification, while Ascococcus is with the Glaeogenae.

Trevisan (1879, p. 137) reworded Cohn's description as follows:
"Cellulae globosae, inordinate in colonias conglobotas pluristratas
densissime consociatae, tegumentis propriis nullis. Coloniae tegumento
communi gelatinoso-cartilagineo crassissimo obvolutae. " He included
it in the subtribe Sarcineae.

Ascococcus Billroth was recognized by Magnin (1880, p. 96) with
the species A. billrothii Cohn. Winter (1880, p. 47) hkewise recognized
the genus as Ascococcus Cohn. He questions, however, the value of
Cohn's genus and also whether the genera of Cohn and Billroth are
based upon the same form. He believes it probable that Ascococcus
Cohn is only a developmental stage of Micrococcus Cohn.

Van Tieghem (1880, p. 150) recognized the genus, and added to it
the species Ascococcus vibrans from the surface of water in which Beg-
giatoa was putrefying.

Grove (1884, p. 15) used practically the same words as Winter in his
discussion of the genus. Van Tieghem regarded Ascococcus as a subdi-
vision of Micrococcus including those forms with cells embedded in gelatin.

GENERAL SYSTEMATIC BACTERIOLOGY 189

Zopf (1885, p. 51) in the third edition of his Spaltpilze, though not in
the preceding, recognizes Ascococcus BiUroth as a Micrococcus with
intensive gelatin production. Hueppe (1885) states that in the genus
Ascococcus the cells are spherical, not in chains, occurring in irregu-
lar masses in spherically segmented zoogloea. Schroeter (1886, p.
153) recognizes "Ascococcus Billroth 1874 (in der Umgrenzung von
Cohn 1875)." According to Fliigge (1886, p. 140) Ascococcus includes
spherical bacteria united into definite slime famihes, colonies solid,
filled throughout with cells, cells in large but indefinite numbers united
into irregular colonies. The species Ascococcus Billrothii Cohn is
discussed. Hansgirg (1888, p. 266) recognized Ascococcus as the second
genus of his subfamily Cystococcaceae. The species A. Billrothii and
a variety thermophilus are described by Hansgirg (188, p. 88). This
variety was found in warm waters, cells Ifx thick, colorless, spherical
or almost egg shaped, united into families, from 6 to 60m, colorless or
yellowish. The same species and variety were included by De Toni
and Trevisan (1889, p. 1038). They note that the divisions of the
cocci occur in three directions, emphasizing thereby that the cells
do not occur in chains. The genus was included by Billet (1890, p.
24) and by Cornil and Babes (1890, p. 148). Hansgirg (1890, p. 24)
named an Ascococcus cellaris. He believes the Thiopolycoccus of Wino-
gradsky should be regarded as a synonym. His description of A.
cellaris follows:

Zellen kugelig oder fast kugelig, sehr viele zu kugeligen oder rundlichen,
soliden, 6 bis 20ju breiten Familien, mehr weniger dicht gehauft, seltener fest
zusammengepresst, mit einer gemeinsamen, nicht geschichtlichen Gallert Hiille
umgeben, 0.7 bis Iju breit, farblos.

Sternberg (1892, p. 17) recognizes the genus Ascococcus, and describes
Ascococcus Billrothii giving as its origin "Found by Billroth in putre-
fying flesh infusion." Miller (1892, p. 75) described a new species,
Ascococcus huccalis from the mouth. He says:

Ein in etwas unregelmassigen Kokken resp. Diplokokken einzeln oder in
Ketten vorkommendes Bacterium. Dasselbe bildet kleine erhabene glanzende,
in alteren Culturen wie winzig kleine Glasperlen aussehende Colonieen welche
sich besonders da durch auszeichnen dass sie eine knorpelartige consistenz be-
sitzen und sich mit der Nadel nicht heben lassen, sondern vor derselben auf der
Oberflache der Gelatine herumgleiten.

Mac6 (1897, p. 335) designates the genus as Ascococcus Billroth.
Migula (1897, p. 18) likewise concluded that Ascococcus is synonymous

190 GENERAL SYSTEMATIC BACTERIOLOGY

with Micrococcus, the species becoming Micrococcus Billrothii (Cohn)
Migula. The species Ascococcus cantrahridgensis described by Hankin
from the mouth of a student at Cambridge is noted by Lehmann and
Neumann (1901, p. 179). Winslow and Rogers (1905, p. 669) revived
Cienkowski's name, Ascococcus mesenteroides as the type of their
emended genus Ascococcus (Cohn) Winslow and Rogers. This was
characterized later at greater length (1908, p. 136). The Winslows
discuss the name Ascococcus Billrothii of Cohn. They conclude that
because of the cheesy odor and frequent confusion by Cohn of cocci
and bacilli, that in all probability Cohn studied a rod-shaped organism.
It would seem that they are in error in this matter, for the illustrations
accompanying Cohn's description are very distinctive. They also
note Cienkowski's use of the term Ascococcus and state

Van Tieghem (1878) a little later worked on the same form and substituted
for Ascococcus the generic name Leuconostoc in order to emphasize the resem-
blance between the zoogloea-forming coccus and the blue-green alga, Nostoc.

This would seem to be scarcely a full statement of the case. Van
Tieghem concluded that the organism of Cienkowski differed so mark-
edly from Cohn's description of Ascococcus that a new generic designa-
tion was required. The Winslows emend the diagnosis of Ascococcus
to conform to modern conceptions. It would seem that they are misled,
perhaps, by the apparent appropriateness of the name Ascococcus.
There seems to be little question but that Cohn's Ascococcus was a
form entirely distinct from A . mesenteroides, and the generic designation
should be reserved for Cohn's species. If Van Tieghem was in error
in believing that Cienkowski's organism deserved generic separation
from Ascococcus, then the name used by the latter may be revived. It
should be noted that Winslow's designation Ascococcus (Cohn) Winslow
and Rogers, is incorrect. Article 41 of the International Rules reads:
"An alteration of the constituent characters or of the circumscription
of a group does not warrant the quotation of another author than the
one who first published the name or combination of names." The name
Ascococcus was rejected by Erwin F. Smith (1905, p. 174). Vuillemin
(1913, p. 520) lists Ascococcus Billroth 1874 as one of his "Formogenera
conservanda."

Mace (1913, p. 433, 435, 646) is almost alone among recent writers
in recognition of this generic name. He gives an extended description
of A. Billrothii Cohn and A. equi Mace.

GENERAL SYSTEMATIC BACTERIOLOGY 19 1

Buchanan (1915, p. 5) discussed at length the use of the name by
Winslow and Rogers. It is probable that Migula's conclusion that
Cohn's Ascococcus is a growth form of a Micrococcus is correct. The
species A. Billrothii Cohn has never been certainly recognized since
described. The status of the genus is quite uncertain. Its type is

A. Billrothii Cohn.

Ascokokkus. A variant of Ascococcus.

Askokokkus. A variant spelling of Ascococcus Cohn used by Hueppe
(1886, p. 145). He includes this as an "Untergattung" of his "Arthro-
Kokkaceen."

This spelling has been used not infrequently by German writers.

Astasia. This name was first applied to a protozoan genus bj'
Ehrenberg. In this sense it is also given by Perty (1852, p. 167).
More recently the same word has been used as a generic name by
Meyer (1897, p. 185) for a new species of rod-shaped bacteria, Astasia
asterospora. Two characteristics of the organism as described by Meyer
differentiated it from other genera. The spore is barrel-shaped, ribbed
longitudinally, and with a well differentiated extine and intine; the
flagella are produced in bunches, laterally. The original description
was later modified (1898, p. 49). Migula (1900, p. 528) regards Astasia
as a synonym of Bacillus and writes Bacillus asterosporus (IMeyer)
Mig. The organism is described by Migula as a motile rod, usually
single, seldom in short chains, 1 to 1 . 3/i thick, 3 to 6/x long, becoming
motionless before spore formation. Spores ovoid, with longitudinal
striae, star-shaped in cross section, with polar germination. Flagella
distributed over the entire body. On sterilized beet slices it develops
as a gray, glassy, gelatinous layer, which spreads so that after five days
the slice is covered with a thin gelatinous layer, finally showing gas
bubbles. The middle lamellae of the beet are dissolved so that the
medium becomes soft. Spores are found after five days, in addition
to resting and swarming rods. In dextrose gelatin rapid liquefaction
occurs, with some gas bubbles. It grows in nutrient solution, causing
a decided clouding. IMigula groups this organism with Bacillus subtilis,

B. ramosus, etc. The cultural characteristics with the exception of gas
production seem to relate it quite definitely to these forms.

Buchanan (1918, p. 38) used this name as a subgeneric designation
under the genus Bacillus, with the description "Motile rods, spores
ovoid with longitudinal stripes, star shaped in cross section." The
type is designated as Bacillus (Astasia) asterospora (Meyer) jMigula.

Asterococcus. A generic name proposed by Borrel, Dujardin-
Beaumetz, Jeantet and Jouan (1910, p. 179) for the organism causing

192 GENERAL SYSTEMATIC BACTERIOLOGY

bovine peripneumonia. The single species was named Asterococcus
mycoides. The genus may be characterized as follows: Pleomorphic
cells, appearing at different stages as cocci isolated and in chains, and
as rods and filaments variously branched and swollen, apparently as
involution forms resembling frequently the bacteroids of legumes, cells
extremely minute, almost ultramicroscopic. Non-motile. No spores.
Stain with difficulty, best with Giemsa. Growth in cultures only
in presence of serum or hemoglobin. Apparently the organism has not
again been seen or recorded.

The genus was recognized by Buchanan (1918, p. 44) and included
in his subtribe Hemophilinae.

Astrobacter. A generic name given by Jennings (1896, p. 312)
to an organism found in stagnant water near Rubingen by Coppen-
Jones. Slides stained by Loeffler's method to demonstrate the flagella
of Spirillum undula when examined were found to show the organism in
question. The original material had been lost, so that the entire
description is based upon observation of the mounted slides.

A simple rod-like bacterium. Initial cell division is marked by a
bifurcation of the end of the rod, producing a Y-shaped form. The
split deepens, and others occur, making tri-radiate types with the rays
spreading at an angle of 120°. Four rayed forms with various angles
occur, as do also forms with as many as eight rays. The rays do not
appear to all lie in a single plane. In a few cases transverse constric-
tions of some of the rays were noted. Whether this genus has been
based upon any form which actually occurs in nature has not been
proved. It is entirely possible that the so-called organisms are arte-
facts of some type. Until there is a demonstration of the living organ-
isms the generic name Astrobacter Jennings may well be held in abeyance.
It has apparently never been recognized or used by other investigators.
It is definitely rejected by Erwin F. Smith (1905).

Athiorhodaceae. A family of the order Rhodobacteria proposed by
Molisch (1907, p. 28) to include those forms that do not possess free
sulfur granules in the cell contents. The following genera, described
in the same work, make up this family: Rhodobacillus, Rhodobacterium,
Rhodocapsa, Rhodothece, Rhodococcus, Rhodovibrio, Rhodocystis, Rhodo-
nostoc, and Rhodospirillum. The organisms all develop in the presence
of light. They possess two pigments called bacteriopurpurin and
bacteriochlorin.

The family name does not conform to the botanical code in that it is
not derived from the name of any one of the component genera. It is
made a synonym of Rhodobacterioideae by Buchanan (1918, p. 128).

GENERAL SYSTEMATIC BACTERIOLOGY 193

Aurococcus. A generic name proposed by Winslow and Rogers
(1906, p. 540) to include the orange cocci. The generic diagnosis
given is:

Parasites. Cells in groups and short chains, very rarely in packets. Gener-
ally stain by Gram. On agar streak growth of orange color. Sugars fermented
with formation of small amount of acid. Gelatin often liquefied very actively.
May or may not reduce nitrates. Includes A. aureus (Rosenbach.)

The same genus was later discussed by the Winslows (1908, p. 255).
They include three species, Aurococcus aureus (Rosenbach) Winslow,
Aur. aurantiacus (Schroter, Cohn) Winslow, and Aur. mollis (Dyar)
Winslow.

For the generic name Aurococcus Winslow and Rogers to be estab-
lished as valid, it must be shown that the generic name Staphylococcus
which is displaced is invalid. The latter name was proposed by Ogston
(1883, p. 27), but first used as a generic name by Rosenbach (1884, p. 12)
who described a Staphylococcus pyogenes aureus and a Staphylococcus
pyogenes albus. The former is the type chosen for Aurococcus Winslow
and Rogers. On a later page, Rosenbach uses the combination Staphy-
lococcus aureus for the same organism. The genus Staphylococcus
Rosenbach is split by Winslows into the two genera Aurococcus and
Albococcus, and the original generic name discarded. Article 45 of the
International Rules of Botanical Nomenclature states.

When a genus is divided into two or more genera, the name must be kept and
given to one of the principal divisions. If the genus contains a section or some
other division which, judging by its name or its species, is the type or the origin of
the group, the name is reserved for that part of it.

It would seem that the Winslows have shown no adequate nomen-
clatural reason for abandoning the generic name Staphylococcus. It
should, therefore, be retained for one of their genera. Inasmuch as
Staphylococcus aureus was described first, and is in a sense the type of
the group, the name Aurococcus should be reduced to a synonym of
Staphylococcus. This genus can be emended, if desired, to exclude the
white forms, thus making the genus Albococcus valid.

These facts were pointed out by Buchanan (1915, p. 8) and agreed
to by the Committee of the Society of American Bacteriologists (1917,
1920) and by Winslow, Rothberg and Parsons (1920, p. 161).

Azotobacter. Agenusof bacteria created by Beijerinck (1901, p. 561)
to include certain non-symbiotic nitrogen fixing organisms of the soil.
Beijerinck gives the following diagnosis of the genus:

194 GENERAL SYSTEMATIC BACTERIOLOGY

Dicke in jungem Zustande meist als grosse Diplokokken oder als Kurzstab-
chen vorkommende Bakterien mit hyalinem, oft eine Vakuole fiihren dem Inhalte
und schleimiger Wand von sehr verschiedenen Dicke. Jiingere Zustande mehr
oder weniger beweglich vermittels einzelner polarer oder in polaren vier — bis
zehnzahligen Biindeln angeordneten, kurzen Cilien, welche umgefahr so lang sind,
wie die Bakterien selbst. Sporen fehlen, das heisst, wachstumfahig in Nahrlosun-
gen mit geeigneten Kohlenstoff quellen, welche sehr arm sind an Stickstoffver-
bindungen assimiliert den atmosphaerischen Stickstoff, und ist dadurch in Bezug
auf die iibrige Mikrobenwelt konkurrenzfahig Optimum temperature 28°.

The type species named was Azotobacter chroococcum.

Beijerinck and van Delden (1902, p, 3) again described the genus.
The genus was rejected by Erwin F. Smith (1915). It was accepted by
Stockhausen (1907, p. 88), The genus is quite generally recognized
by writers on agricultural bacteriology. Orla-Jensen (1909, p. 328)
changes the name of this genus to Azotomonas and places it in his family
Oxydobacteriaceae .

Lohnis and Hanzawa (1914, p. 1) claim to have demonstrated that
the organisms of this genus may at certain stages in their life his-
tory produce endospores. They conclude that Azotobacter is therefore
an invalid synonym of Bacillus. The type species is renamed Bacilhis
azotobacter. It may be noted that even though the genus should be
Bacillus, the species should be designated B. chroococcus in accordance
with the botanical rules.

Winslow et al. (Committee 1917, p. 552) and Bergey et al. (1923, p. 38)
accept the genus with the following diagnosis :

Relatively large rods, or even cocci, sometimes almost yeast-like in appear-
ance, dependent primarily for growth energy upon the oxidation of carbohydrates.
Motile or non-motile; when motile, with tuft of polar flagella. Obligate aerobes
usually growing in a film upon the surface of the culture medium. Capable of
fixing atmospheric nitrogen when grown in solutions containing carbohydrates
and deficient in combined nitrogen. The best-known free-living nitrogen-fixing
bacteria of the soil.

The same description is used by the Committee in 1920 (p. 203).
Buchanan (1918, p. 46) describes the genus as follows:

Relatively large rods, or even cocci, sometimes almost yeast-like in appear-
ance, dependent primarily for growth energy upon the oxidation of carbohydrates ;
obligate aerobes, usually growing in a film upon the surface of the culture media.
Capable of fixing atmospheric nitrogen in considerable amounts when grown in
solutions deficient in combined nitrogen. Motile or non-motile, if the latter, with
polar flagella.

GENERAL SYSTEMATIC BACTERIOLOGY 195

It is probable that Azotobacter Beijerinck may be regarded as a valid
genus.

Azotobactereae. A tribe of the Nitrobacteriaceae suggested by Wins-
low et al. (Committee Soc. Am. Baet., 1920, p. 203), to include the
"nitrogen fixing bacteria." The genera Rhizohium and Azotobacter
were included. Bergey et al. (1923, p. 38) include this as the second
tribe of the family Nitrobacteriaceae. Probably the spelling should be
emended to Azotobacterieae.

Azotomonas. This generic name was proposed by Orla-Jensen (1909,
p. 484) to replace the older name Azotobacter Beijerinck (1901, p. 561)
to conform to his rule that organisms with polar flagella should bear
generic names terminating in -monas. It should be regarded as invalid
because of the priority of Azotobacter.

Babesia. A genus of bacteria created by Trevisan (1889, p. 29)
to include two species of cocci, one associated with yellow fever and
described by Babes (1883,) and the other with erysipelas
chronica. It was included as the fourth genus of his tribe Strepto-
coccee. The diagnosis given by De Toni and Trevisan (1889, p. 1054)
is as follows :

Cocci ellipsoidei, longitudinaliter binatim seriati (diplococci longitudinales)
in filament a moniliformia, pseudodichotoma nuda (i.e., nee capsulis nee vaginis
obducta) concatenati. Arthrosporae macrosomae in apice filamentorum
obvenientes.

The genus is differentiated from Streptococcus by the pseudodichot-
omous branching of the filaments and by the production of arthrospores
at the ends of the filaments. The generic description corresponds with
that of no organism at present known. The two species, B. xanthopy-
retica Trev. and B. erysipeloides Trev. were so inadequately described
as not to be recognizable. The genus name has never come into use.
It may be regarded as invalid or possibly as a synonym of Streptococcus
(Erwin F. Smith 1905, p. 174).

Babesia xyanihopyretica Trev. {Streptococcus xanthopyreticus Trev.)
may be regarded as the type.

Babesia is also used as a generic name in the pathogenic protozoa.

Bacillaceae. A family proposed by Fischer (1895, p. 139) with the
spelling Bacillacei and with the following diagnosis :

Vegetationskorper einzellig, gerade mit ausgesprochener Langsachse, bald
kurz ellipsoidiseh, bald gestreckt stabchenformig : Theilung immer in derselben
Richtung, senkrecht zur Langsachse mit oder obne Kettenwuehs und Bewegung.
Sporen theils endospor, theils arthrospor.

196 GENERAL SYSTEMATIC BACTERIOLOGY

In the translation of the Vorlesungen by Coppen Jones (1897, p. 32)
this is spelled Bacillaceae. In the second edition (1903, p. 60) the diag-
nosis given is:

Vegetationskorper cylindrisch, ellipsoidisch, eiformig, gerade; bei den kurzen,
fast kugeligen Formen und die Trennung von Kokken schwer; Teilung immer
senkrecht zur Langsachse, als Wuchsform nur unverzweighte Ketten.

In the original description four subfamilies are listed. Bacilli,
Bacterinei, Bactrillei and Bactridei. Later (1903) the three subfamilies
recognized were Bacilleae (with four genera) Clostridieae (two genera)
and Plectridieae (two genera).

Schmidt and Weis (1902, p. 91) likewise used this family designation,
including the three genera Bacterium, Bacillus and Pseudomonas with.
the following description :

Die Zellen sind cylindrisch, ktirzer oder langer stabchenformig, gerade. Die
Zellteilungen geschehen nur nach einer Richtung des Raumes. Vor der Teilung
strecken sich die Zellen m einer senkrechten Richtung zu der spater gebildeten
Scheidewand. Endosporbildung bei mehreren Arten bekannt.

The name has also been used as a group designation by Fliigge (1908).

This family name is also used by Benecke (1912, p. 188) to include
the rod-shaped bacteria without sulphur or bacteriopurpurin, un-
branched and not forming a pseudoplasmodium.

Winslow et al. (Committee Soc. Am. Bact., 1917, p. 561) used this as
a designation for their seventh family of the Euhacter tales. The diag-
nosis is: "Rods producing endospores, usually Gram-positive. Flagella
when present peritrichic. Actively decompose protein media through
the agency of enzymes."

Winslow et al. (Committee Am. Soc. Bact., 1920, p. 212) in their final
report used the same diagnosis.

Castellani and Chalmers (1920, p. 601) state:

Cette famille peut etre d^finie : Eubacteriales avec cellules longeres ou courtes,
flagell^es ou non flagell6es; sporogenes ou non sporogSnes, mais toujours cylin-
driques et droites et se divisant seulement dans une direction.

Le genre type est Bacillus Cohn 1872, mais ce genre et I'autre genre ancien,
Bacterium, renferment un si grand nombre d'especes et de vari6t4s que nous avons
essay6 de simplifier leur diagnose en d^finissant les tribus et les genres suivant.

They divide the family into 10 tribes.

Bergey et al. (1923, p. 272) included this as the fifth familj^ of the order
Eubacteriales with the description : "Rods producing endospores, usually

GENERAL SYSTEMATIC BACTERIOLOGY 197

Gram-positive. Flagella, when present, peritrichous. Often decom-
pose protein media actively through the agency of enzymes."

Two genera, Bacillus and Clostridium are included.

Bacillacei. A family name proposed by Fischer (1895, p. 139).
For discussion, see Bacillaceae (the corrected form).

Bacilleae. A tribe established by De Toni and Trevisan (1889, p.
941) with the following diagnosis " Baculi cocci nunquam capsulis
membranaceogelatinosis involuti." It is the first tribe of the subfamily
Baculogenae Trev. It includes the sub-tribes Pasteurieae (one genus)
Thiodictyeae (one genus), Eubacilleae (six genera) and Spirilleae (two
genera) .

With the spelling Bacillei this name was also used by Fischer (1895,
p. 140) as a subfamily of the family Bacillacei to include all rod-shaped
organisms "Unbeweglich, ohne Geisseln." Four genera were included,
Bacillus, Bactrinium, Bactr ilium and Bactridium.

The name was used by Buchanan (1918, p. 33) as a tribe of the family
Bacteriaceae with the following description :

Cells rod shaped, never spiral or strictly filamentous, single or in chains,
usually motile by means of peritrichous flagella, producing endospores under
suitable conditions of growth, usually Gram-positive.

The four genera Bacillus, Plectridium, Clostridium and Metabacterium.
were included.

Castellani and Chalmers (1919, pp. 933, 959) propose this as a tribe
of the family Bacillaceae. Apparently they are in error in ascribing
the name to Castellani and Chalmers 1918. They state: ^'Bacillaceae
growing well on ordinary laboratory media and producing endospores.
One genus only is included, Bacillus, the type genus." They again
describe it in 1920 (p. 601).

Bacillee. A name given by Trevisan (1889, p. 12) to the third
tribe of the sub-order Baculogene. It is ascribed to Trevisan (1887).
The description given is:

"Baculi, filamenti e cocchi non mai racchiusi in capsule membran-
aceo-gelatinose." Twelve genera are included, Pasteuria, Winograd-
skya, Thiodictyon, Mantegazzaea, Bacillus, Pasteurella, Cornilia, Clos-
tridium, Vibrio, Pacinia, Spirillum and Syiromonas.

Bacillei. A subfamily name incorrectly spelled used by Fischer (1895,
p. 140). For discussion, see Bacillaceae.

Bacillococcus. A casual name used by Frankland (1890, p. 122)
for a nitrifying soil organism.

198 GENERAL SYSTEMATIC BACTERIOLOGY

Bacillopsis. A generic name suggested by Petschenko (1908, p. 359)
for an organism questionably bacterial. Enlows (1920, p. 19) states:

Type species (monotypy). B. stylopygae. Found in the digestive tube of
Blatta orientalis {Stylopyga orientalis). Length 10m, by 2.5/* wide. A slightly
curved rod, with one end slightly pointed, the other obtuse. Nucleus is present.
Also highly refractive "corpuscules" in the transparent protoplasm, which are
probably nutritive substances. Reproduction by a sort of budding, in which the
very small daughter cell remains attached to the mother cell by a delicate fila-
ment until it has attained the size of mother cell. After this stage of active
growth there is a stage in which filiform prolongations appear, and the "corpus-
cules" unite into 1 or 2, rarely 3 large round bodies. Vacuoles observed. In
doubt as to position of organism, but does not think it belongs with the bacteria.
(Has been included by other authors among the bacteria.)

Bacillus. A generic name established bj^ Cohn (1872, p. 174) to
include three species of rod-shaped organisms, Bacillus subtilis, B.
ulna and B. anthracis. He included in this genus those rod-shaped or-
ganisms that grow in filaments. The type of the genus was B. subtilis.
A discussion by Cohn of spore production in Bacillus subtilis embodied
the first accurate description of endospores. His inclusion of the
anthrax organism indicates that in his conception of the genus motility
was an unimportant characteristic. In a later paper, Cohn (1875,
p. 141) included the genus Bacillus under the tribe Nematogenes and
characterized it as follows :

Cells disposed in filaments, filaments not branched, free or interlaced, cylin-
drical, colorless, articulations not very distinct, very slender and short.

It will be noted that in the preceding description emphasis is placed
upon the occurrence of the rods in short chains or filaments. Sporula-
tion and motility were not included in the generic diagnosis. Within
the genus were listed both motile and non-motile forms. Sporulation
was discussed in certain of these species, but not rated definitely as a
generic character. These facts are emphasized because subsequent
generic designations frequently stress other characteristics.

Winter (1880, p. 38) uses the genus practically in the sense of Cohn.
He states:

Zellen verliingert cylindrische, fast stets in geraden, stielrunden (nicht oder
wenig eingeschniirten) Reihen oder Fiiden zusammenhangend, durch Querthei-
lung sich vermehrend. Sie bilden Zoogloeen, kommen aber oft auch in dichten
Schwarmen (ohne Gallertausscheidung) vereinigt vor. Fortpflanzung durch
Sporen.

GENERAL SYSTEMATIC BACTERIOLOGY 199

This is the first definite inclusion of the character of spore production
in the generic diagnosis, but this should not be emphasized as a differ-
ential character, for in the description of Bacterium there is the state-
ment "Sporenbildung ahnlich wie bei Bacillus."

Luerssen (1879, p. 22) accepted Cohn's classification practically
without modification. Emphasis is placed upon the occurrence of the
organism in jointed threads, and no mention is made of sporulation.
Magnin (1880, p. 87) used the same description.

De Bary (1884) influenced largely by the idea of bacterial pleomor-
phism, abandoned the old genus Bacterium and put all endosporous rods
into the genus Bacillus and all arthrosporous rods and those for which
no spores are known into Arthrohacterium. De Bary states: (trans-
lation by Garnsey and Balfour 1887, p. 460)

The forms included under this term (endosporous bacteria) are chiefly known
in the growth-form of single rods consisting of one or a few cells, or of rods joined
together and forming long filaments; they may also be collected together into
larger gelatinous masses or membranes. In some forms the rods are spirally
twisted, and these I name here Spirillum of Van Tieghem. Others do not show
these curvatures, but are either straight or very slightly bent, all these I include
under the term Bacillus and place under that genus all the endosporous forms
which have been hitherto known either as Bacillus or as Clostridium, Bacteridiwn,
Vibrio, or by some other name. All non-endosporous forms bearing these names
on account of their growth form are, of course, excluded from the group.

It will be noted that this is a direct abandonment of the generic
conception of Cohn although the type species may well be said still to be
B. suhtilis.

Van Tieghem (1884, p. 1110) uses the term Bacillus as a form group
to include those rods which are not associated but are united into fila-
ments of greater or less length, practically in the sense of Cohn. Grove
(1884, p. 26) follows Winter minutely. Trevisan (1885, p. 94) included
in this genus those organisms showing three stages of development, as
rods, filaments and cocci. In the rod or bacillus stage the cells are
normally cylindric, or ellipsoid, straight or slightly curved, jointed or not,
colorless or colored, cytoplasm equally distributed. Spores single in the
rods. Filaments and cocci transitorj^ stages. He included descrip-
tions of thirty-one species, the first one described being Bacillus
anthracis Cohn. The views of Van Tieghem were in part accepted bj^
Zopf in the third edition of "Die Spaltpilze" (1885, p. 61). In previous
editions the term Bacillus was regarded merely as the designation of a
growth form of a Bacterium. His diagnosis in the third edition is:

200 GENERAL SYSTEMATIC BACTERIOLOGY

"Coccen und Stabchenformen oder auch nur Stabchen in gewohnlichen
oder gewundenen Faden, Sporenbildung vorhanden in Stabchen oder
in Coccen auftretend." Although the definition is greatly modified
by the current ideas of bacterial pleomorphism the emphasis is placed
upon the development of endospores by the members of the genus.
Hueppe (1885) likewise included in the genus Bacillus those rods that
developed endospores.

Flligge, (1886, p. 136) used "Bacillen" to include rods whose length
was two to twenty times the diameter; returning in a sense to the con-
ception of Cohn.

Maggi (1886, p. 173) included this genus, without description, in his
fourth order, Desmobacteries. Eleven species are listed.

Schroeter (1886, p. 156) considers the genus Bacillus to include organ-
isms with long cjdindric vegetative cells, daughter cells often remaining
united for a time in a chain, often actively motile, with endogenous
spores produced singly in cells that do not become swollen when sporu-
lating. In some species the cells grow into long filaments just pre-
ceding sporulation (Streptobacter) . In a rather loose fashion a some-
what similar meaning is given by Cornil and Babes (1890, p. 165) ; these
authors emphasize sporulation. Hansgirg (1888, p. 264) includes
Bacillus as the first genus of the subfamily Microbacteria. He divides
the genus into two sections or subgenera, Eubacillus and Chromo-
bacillus. Trevisan (1889, p. 12) included Bacillus as the fourth genus
of the tribe Bacillee. The generic description is "Baculi cilindrici,
cilindracei o ellissoidi, con protoplasma uniformemente diffuso. Spore
microsome (cioe che non mai raggingono un diametro maggiore del
diametro transversale normale dei baculi entro cui si formano) pro-
venienti in baculi normali immutati." The generic synonyms are
given as "Metallacter e Chromalium Perty (1852); Bacteridium Davaine
(1863); Bacillus e Bacterium F. Cohn (1873); Streptobacteria Billroth
(1874) ; Pollendera Trevisan (1884) ; Coccobacillus Leube (1885) ; Proteus
Hauser (1885) ; Bacteriopsis Trevisan (1885) ; Coccothrix Lutz (1886) ;
Sclerothrix Metschnikoff (1888). In all 201 species were listed. De
Toni and Trevisan (1889, p. 1889) elaborated the diagnosis of Bacillus
somewhat to allow of the differentiation from it of numerous related
genera. Their diagnosis is as follows :

Baculi cylindrici vel cylindracei, recti vel leviter curvi, apicibus conformibus
rotundatis vel truncatis, plasmate uniformiter diffuse. Filamenta vulgarissima
e baculis, coccis nullis interjectis conflata. Sporae (endosporae) microsomae, in
baculis normalibus immutatis obvenientes.

GENERAL SYSTEMATIC BACTERIOLOGY 201

A large number (228) of species are described. Billet (1890, p. 23)
described Bacillus as "Formes rectilignes, element 5 a 10 fois plus long
que large."

Bamngarten (1890) was apparently the first to use the generic name
Bacillus to include all rod-shaped, "monomorphic" bacteria, prac-
tically merging with it the genus Bacterium. This conception was
adopted by Sternberg (1892, p. 18) who defined the genus as follows:

Rod-shaped and filamentous (not spiral) bacteria in which there is no differen-
tiation between the extremities of the rods; reproduction by binary division in
a direction transverse to the long axis of the rods, or by binary division and the
formation of endogenous spores; rigid or flexible, motile or non-motile.

This use has led to the rapid "vulgarization" of the term Bacillus
until it is frequently now noted as being used in two senses, a general
sense with reference to shape, and as a genus name. This has con-
tributed to much confusion in the literature.

Ludwig (1892) defines the genus as containing small rods which pro-
duce endogenous spores.

Clements (1894, p. 27) fists four species, with the following generic
description :

Cells cylindrical, straight or curved, motile, filaments present at time of spore
formation, falling into small cells as soon as the endogenous spore is formed.

ISIigula (1894, p. 237) emended the genus Bacillus Cohn, the diagnosis
reading "ZeUen mit liber den ganzen Korper angehefteten Bewegungs-
organen, oft mit Endosporenbildung. (Z. B. Bacillus subtilis Cohn.)"
Migula (1895, p. 25) later elaborated this conception. He based his
principal generic designations upon differences in flagellation. Accept-
ing B. subtilis as the generic type, he characterized the genus as made
up of straight rods with flagella scattered over the entire cell body.
Sporulation and filament formation he considered secondary to
flagellation.

The second emendation in 1895 of Bacillus was that of Fischer (1895,
p. 140). This author rejects Migula's use and states:

Unbeweglich, ohne Geisseln, mit Endosporen in unveranderten, nicht spindeli-
gen Oder kopfigen Stabchen; eine schwache allseitige Vergrdsserung derStabchen;
bei der Sporenbildung kommt zuweilen vor. Sporen in der Mitte oder am Ende
der Stabchen, Bacillus anthracis Cohn Bacillus Carotarwn A. Koch.

202 GENERAL SYSTEMATIC BACTERIOLOGY

Later (1897, p. 32) he says

The word Bacillus might then be used, in memory of Koch's first work for all
those species which, like the anthrax parasite, are non-motile and retain their
shape during sporulation.

This of course constitutes a direct abandonment of Bacillus subtilis
as the generic type.

Lehmann and Neumann (1898, p. 279) returned to the differentiation
of the genus upon the basis of endospore production. Their diagnosis
reads: "Gerade Stabchen haiifig zu Faden auswachsend. Dicke oft
betrachthch, selten unter 0.6, meist liber 0.8ju. Endosporen bildend."

Migula later expanded his classification (1897, p. 47) and again em-
phasized the peritrichous flagellation of the cells as the principal
diagnostic character. Mace (1897, p. 484) used as a diagnosis "Ele-
ments in the form of rods, short or long, straight or slightly bent."
He concludes that the Bacteridium of Davaine, the Clostridium of
Prazmowsky, the Tyrothrix of Duclaux, the Proteus of Hauser are syno-
nyms. Hewlett (1898, p. 18) includes all rod-shaped bacteria under
the genus Bacillus. Migula (1900, p. 515) again defined Bacillus as
made up of peritrichous rods. He says:

Kiirzere oder langere, stabchenformige bis ovoide gerade Zellen, oft zu ziem-
lich langen Faden verbunden, beweglich, mit iiber den ganzen Korper zerstraut
stehenden, wellig gebogenen Geisseln. Endosporenbildung ist haufig.

Lehmann and Neumann (1901, p. 124) consistently adhere to the
diagnostic importance of endospores, and include all spore bearing rods
in this genus. Chester (1901, p. 199) follows Migula in basing his diag-
nosis upon peritrichous flagellation. The same description is used by
Kendall (1902, p. 484). Schmidt and Weis (1902, p. 91) follow Migula.
Matzuschita (1902, p. IV) included all rod-shaped organisms. Allan
J. Smith (1902, p. 270) gives the generic description "Cells with flagella;
peritrichous; endospores present or absent." Fischer in the second
edition of his lectures (1903, p. 60) again defines Bacillus as comprising
the non-motile rods. Migula (1904, p. 145) reaffirmed peritrichic flagel-
lation as important. He is followed by Erwin F. Smith (1905, p. 160),
Ellis (1909, p. 6), Frost (1911, p. 57), Schneider (1912, p. 23) and many
other authors. Orla-Jensen (1909, p. 344) used the name Bacillus to
designate organisms of the type of B. mijcoides, placing the genus in his
family Alkalibacteriaceae. These organisms are said to require organic
nitrogen, free oxygen, produce spores and cause decay. Conn (1909,

GENERAL SYSTEMATIC BACTERIOLOGY 203

p. 12) apparentl}'" introduced still another conception of Bacillus when
he included in the genus all "Rod-shaped bacteria with flagella and
consequently motile "

Heim (1911, p. 250) and Lohnis (1913, p. 45) included in Bacillus
the spore-forming rods. Vuillemin (1913, p. 526) comes to the con-
elusion that the name Bacillus has been so vulgarized by various usages
among bacteriologists, that it should be regarded merely as a form genus
without nomenclatural status. As a substitute for this generic desig-
nation he revives the name Serratia (q.v.) and gives as the type Serratia
suhtilis Vuillemin.

Winslow et at. (Committee Soc. Am. Bact. Preliminar}^ Report, 1917,
p. 562) included the spore bearing rods in this genus with the following
diagnosis: "Aerobic forms. Mostly saprophytes. Liquefy gelatin.
Often occur in long threads and form rhizoid colonies. Form of rod
usually not greatly changed at sporulation." Bacillus subtilis Cohn
was designated as the type.

Buchanan (1918, p. 33) discussed in detail the generic designation,
and defined the genus as follows :

Cells rod shaped, straight or at least never spiral, motile by diffuse flagella or
non-motile. Endospores produced under favorable conditions, not usually dis-
torting the cell, usually Gram-positive. Growth usuallj'^ good on laboratory
media; commonly liquefying gelatin. Aerobic or facultative.

Three subgenera were recognized, Eu- Bacillus, Bacteridium and
Astasia.

Winslow et al. (Committee Soc. Am. Bact., 1920, p. 212) in their final
report use the same diagnosis as in 1917. This is also used by Bergey
etal. (1923, p. 272).

The usages of various authors may be summarized as follows :

1. Bacillus. Rod-shaped organisms occurring in filaments or
chains. Spore production, flagella distribution, and motility not
emphasized. Cohn (1872, and 1875), Magnin (1878), Winter (1879),
Luerssen (1879)?, Van Tieghem (1884), Grove (1884), Fliigge (1886),
Schroeter (1886).

2. Bacillus. Rods producing endospores (some authors recognizing
other spore-bearing genera in addition). De Bar}' (1884 and 1887),
Zopf (1885), Hueppe (1885), Cornil and Babes (1885 and 1890), De
Toni and Trevisan (1889), Ludwig (1892), Freudenreich (1894), Leh-
mann and Neumann (1896), Chester (1897), Fliigge (1908), Orla-Jensen
(1909), Heim (1911), Lohnis (1913), Winslow et al. (1917, 1920), Bu-
chanan (1918), Bergey (1923).

204 GENERAL SYSTEMATIC BACTERIOLOGY

3. Bacillus. Rods motile by means of peritrichous flagellla. Migula
(1895, 1897, 1904), Chester (1901), Kendall (1901), A. J. Smith (1902),
E. F. Smith (1905), Ellis (1909), Frost (1911), Schneider (1912).

4. Bacillus. Non-motile rods, cylindrical, producing endospores.
Fischer (1895, 1903), Lotsy (1907).

5. Bacillus. Any rod-shaped organism. Baumgarten (1890), Stern-
berg (1892), Mace (1897), Hewlett (1898), Matzuschita (1902).

6. Bacillus. Any motile rod. Conn (1909).

It would seem that the genus name Bacillus should be retained for
the designation of a limited group of organisms, though probably
no harm can come from the use of the term bacillus as a casual name to
indicate rod-shaped organisms in general. It should be emphasized
that when used as a generic designation it is a proper noun, and must be
capitalized, whenever used. Many bacteriologists have ignored this
rule which is followed so carefully by systematists and biologists in
treating all other forms of life. Vuillemin's contention that the use of
bacillus as a vulgar noun leads to confusion is not well premised. The
genus Aster is universally recognized by botanists as valid. This does
not interfere with the use and usefulness of the common name aster
which includes many species not belonging to the genus Aster. By no
means all of the plants commonly known as lilies are placed by the botan-
ist in the genus Lilium. There is no reason why we cannot continue
to speak of the tubercle bacillus even though it does not belong to the
bacterial genus Bacillus.

In some form or with some definition the genus Bacillus should be
retained. The type practically always accepted is B. subtilis. The
definition of Fischer should therefore be abandoned as including only
non-motile forms. He would exclude from the genus its first described
species. The original description of Cohn is scarcely suflScient, for
much stress was laid upon cell grouping and length of cell and not upon
other characters. The use of Migula's diagnosis, including in the genus
all rods with peritrichous flagella, is the cause of great confusion. It
brings into the genus such discordant types as the hay bacillus and the
typhoid bacillus. It excludes from the genus the anthrax bacillus so
closely related to the hay bacillus. It does not result in bringing forms
that are closely related together. Migula's definition should be aban-
doned as not based upon natural affinities. The definitions which would
include aU rods in the genus Bacillus have the merit of simplicity, but
when organisms so diverse in characteristics as the tubercle bacillus,
the typhoid bacillus, the tetanus bacillus, and the anthrax bacillus, are

GENERAL SYSTEMATIC BACTERIOLOGY 205

all included in one genus the simplicity is more apparent than real.
The existence of such diverse forms has led most recent authors to
arrange bacteria into well marked groups. It is the opinion of the
author that the larger groups should be recognized as genera. The term
Bacillus should therefore be restricted. It would seem that it should be
defined more nearly in the terms of De Bary, Zopf, Hueppe, etc., who
emphasized the importance of spore production as a diagnostic character.

Objection may be raised that a definition of Bncillus as a genus made
up of endosporous rods would exclude forms which have lost the power
of spore formation but are in other respects closely related. It is evi-
dently impracticable to base generic diagnoses upon a single character.
Even though an organism be a variant in one or even more characters,
the other resemblances would be sufficient to include the organism in
question in the correct genus. Illustrations of this fact may be taken
from higher plants. The Lombardy poplar is always classified in the
genus Populus. It never produces fruit; it persists solely as the result
of vegetative multiplication. Yet the genus Populus is based in part
upon certain fruit characters. The other characters are so evidently
poplar-like, however, that we do not question the correctness of the
assignment of this species to the genus Populus.

Bactereae. A name given to the fourth tribe of the Bacteriaceae
by Winslow et al. (Committee Soc. Am. Bact., 1910, p. 210). It is
evidently a typographic error for Bacterieae q.v. This spelling is also
used by Bergey et al. (1923, p. 194).

Bacteria. A group name frequently used by authors as synonymous
with Sclnzomycetes. Hansgirg (1888, p. 299) gave the two as synonyms.
Migula used this name with the following diagnosis :

Phycochromfreie Spaltpilzen mit Teilung nach ein, zwei oder drei Richtungen
des Raumes. Viele Arten besetzen Endosporenbildung. Wo Beweglichkeit der
Zellen vorhanden ist, wird dieselbe durch geisselartige Bewegungsorgane, sel-
tener durch undulierende Membranen (Uebergang zu den Phycochromaceen)
vermittelt.

The name in this general sense has been used by many writers.
Heller (1912, p. 449) proposes this as the name of a phylum.

Bacteriaceae. Cohn (1872a, p. 237) under the description of Micro-
sphaera uses the expression "Gruppe der Bacteriaceae." Cohn (1872b)
says

Den gemeinschaftliche Charakter der von mir hier als Bacterien zusammenge-
fassten Organismen scheint nur in Folgen dem zu liegen: Die Bacterien sind

206 GENERAL SYSTEMATIC BACTERIOLOGY

chlorophyllose Zellen von kugliger, oblonger oder cylindrischen, mitunter gedreh-
ter oder gekriimmter Gestalt, welche ausschliesslich durch Quertheiling sich
vermehren, und entweder isolirt oder in Zellfamilien vegetiren.

Apparently the name is used for the entire group of Schizomycetes.

The next reference to a use of this name in Hterature is apparently a
statement of Lanzi (1876, p. 25) who mentions that Prof, Caruel in his
lectures includes the family "Batteriacee" among the "Schizofiti."
It was used in the next year by MacNab (1877, p. 340) and in much the
same sense.

Trevisan (1879, p. 135) used the following description of this family:

Plantae fungales, unicellulares vel pluricellulares, liberae aut in muco matri-
cali amorpho nidulantes, nunc motu proprio spontaneo, vel oscillante, vel rota-
torio, vel flexuoso-repente, vel spirali praeditae, nunc immobiles, acidum carboni-
cum non assimilantes, in aquis plus minusque corruptis, dulcibus, thermalibus
vel marinis, in liquidis fermentantibus, in substantiis putrescentibus, in corpori-
bus animalium viventes. Vegetatio terminalis vel non terminalis. Ramificatio
nulla aut rarissime spuria. Cytioderma flexibile, moUe, tenuissimum. Cytio-
plasma chlorophyllo vel substantia chlorophyllo affini omino carens, achroum
vel coloratum, nucleo destitutum. Multiplicatio divisione cellularum vegeta-
tiva aut in omnes directiones aut semper ad eandem directionem longitudinalem
repetita. Propagatio turn sporis perdurantibus sine foecundatione e cytioplas-
matis condensati metamorphosi genitis, turn microgoniis, in paucis detectis,
e serie cellularum divisione longitudinali et transversa succendanae multiparti-
tarum ortis. Per divisionem formae conservantur, multiplicantur et genera-
tionum series extensissimas evolvuntur; per sporas et microgonia morphae non
raro parentibus plus minus dissimiles, colonias mucosas per cellularum
generationes successivas ortas formantes, nascuntur.

This family name with the aberrant spelling Bacteriaccen was also
used by Zopf (1883, p. 45). He included within it all organisms which
might show four developmental stages, cocci, short rods (bacteria),
long rods (bacilli) and filaments (Leptothrix forms). There is no differ-
entiation of base and tip in the rods. Typical spiral forms are lacking.
Two genera were recognized : Bacterium and Clostridium. In the third
edition of Die Spaltpilze he (1885, p. 51) changes his conception of the
family essentially. He now defines it to include organisms which show
spherical, rod or filamentous growth forms, the latter either straight or
bent. The coccus forms may be lacking. In the rod and filamentous
forms there is no contrast between base and tip. Cell division, so far
as is known, is in one direction of space. Spores present, lacking, or
unknown. Six genera are recognized; Bacterium, Spirillum, Vibrio,
Leuconostoc, Bacillus and Clostridium. Schroter (1886, p. 155) uses

GENERAL SYSTEMATIC BACTERIOLOGY 207

the family name Bacteriacel Zopf as the sole family of his order Euhac-
teria. He includes nine genera: Bacterium, Chromatium, Bacillus,
Clostridium, Spirillum, Spirochaete, Microspira, Myconostoc and Cysto-
bacter. Hansgirg (1888, p. 264) included Bacteriaceae as the first family
of his order Eubacteria, but with no description. It is divided into the
two subfamilies Spirobacteria and Microbacteria.

The classification of Hueppe (1891, p. 30) included two genera only;
Bacterium and Bacillus. Migula (1894, p. 236) says:

Bacteriaceae Zopf emend Mig. Zellen langes oder kiirzer cylindrisch, gerade,
niemals schraubig, gekriimmt: Teilung nur nach einer Richtung des Raumes
nach voraufgegangener Langstreckung des Stabchens.

He (1895, p. 20) included three genera, excluding all spherical, spiral
and filamentous forms. The genera recognized were Bacillus, Bacte-
rium and Pseudomonas. Later (1897, p. 46) he gave the same
definition.

Clements (1894, p. 25) redefined the family as follows:

Minute fungi without mycelium, typically unicellular, or at least the divi-
sions not visible except at the time of the absection of new cells; cells of very
diverse form (round, elliptical, bacillar, or filamentous), generally surrounded by
a gelatinous envelope, one or both ends often provided with 1 to 3 flagella; growth
peripheral, never apical; sexual reproduction undeveloped; asexual reproduction
by simple division or by spores (endo-spores or arthrospores.)

Lehmann and Neumann (1896, p. 103) gave the following definition:

Zellen mindestens 1§ mal, meist aber 2-6 mal so lang als breit, gerade oder in
nur einer Ebene etwas gekriimmt, nie schraubig, zuweilen lange echte oder Schein-
fiiden bildend. Teilung (fast) stets quer auf die Liingsachse nach Streckung des
Stabchens. Mit oder ohne Geisseln. Mit oder ohne Endosporen. Die der
Endosporen entbehrenden Arten soUen nach manchen Autoren zuweilen Arthro-
sporen bilden. Doch ist es nicht moglich, diese von vielen Forschern ganz geleug-
neten "Arthrosporen" diagnostisch zu verwerten.

Mace (1897, p. 438) recognized the family " Bacteriacees." He says:

Ce groupe renferme des Bacteries dont les elements allonges suivant une direc-
tion, ont une longueur qui I'emporte sur la largeur. La forme typique est le
batonnet; il est tantot court et trapu, apparait en coupe optique presque comma
un carre ou comme un court rectangle; tantot sa longeur d(5passe un certain nom-
bre de fois sa largeur. La premiere de ces dimensions pent devenir tres grande par
rapport h I'autre, c'est la forme de filament. Les batonnets ou les filaments sont
droits ou courbes. La courbure peut etre tres simple et ne representer qu'une
faible portion de circonference; elle peut etre compliqu6e, I'^lement d6crit une
spire a tours plus ou moins nombreux, plus ou moins serrils. Quelles que soient

208 GENERAL SYSTEMATIC BACTERIOLOGY

la forme ou la longueur de ces elements, on ne leur distingue jamais d'extremit6
anterieure et d'extr6mit6 posterieure, de base ni de pointe; les mouvements,
lorsqu'ils existent, paraissent toujours se faire egalement dans les deux sens, et
quand des individus se fixent ou plutot s'accolent a un support, leur partie fix^e
ne diff^re en rien de celle qui reste libre.

The definition of Migula of Bacteriaceae has been followed among
others by the following authors: Chester (1901, p. 117), Kendall (1902,
p. 484), A. J. Smith (1902, p. 270), Klocker (1903, p. 332), Migula
(1904, p. 145), Erwin F. Smith (1905, p. 160), Ellis (1909, p. 3), Frost
(1911, p. 57), Schneider (1912, p. 23).

Winslow et al. (Committee Soc. Am. Bact., 1917, p. 560) recognized
this as the sixth family of the order Euhacteriales with the following diag-
nosis: "Rod-shaped cells without endospores. Gram-negative. Flag-
ella when present peritrichic. Metabolism complex, amino-acids
being utilized, and generally carbohydrates."

Buchanan (1918, p. 27) recognized this as the second family of the
Euhacteriales, with the following description:

Cells rod-shaped, straight, or at least not spherical or spiral. Never contain-
ing sulphur granules, nor with bacterio-purpurin, many species pigmented.
May or may not be motile by polar or diffuse flagella. Cells may be single or in
chains. Endospores produced in some genera, not in others. A pseudoplas-
modium never developed. Growth energy not secured by the oxidation of ammo-
nia or nitrites.

In 1920 Winslow et al. (p. 208) describe Bacteriaceae as the fifth
family of the Euhacteriales including seven tribes.

Bergey et al. (1923, p. 84) recognizes this as the fourth family of the
order Euhacteriales with the description: ''Rod-shaped cells without
endospores. Motile or non-motile. Metabolism complex, amino-
acids being utilized, and generally carbohydrates. Usually Gram-
negative." Nine tribes are included.

It is evident that while the earlier writers used this name as a desig-
nation of the entire group of bacteria, the later writers have uniformly
regarded it as a family within the group.

Bacteriaceen. An aberrant form of spelling of the family Bacteria-
ceae iq.v.) used by Zopf (1884, p. 45, and 1885, p. 51).

Bacteriacees. An aberrant form of spelling of the family Bacteria-
ceae iq.v.) used, among others, by Cornil and Babes (1890, p. 151).

Bacteriacei. An aberrant form of spelling of the family Bacteriaceae
iq.v.) used by Schroter (1885, p. 155).

GENERAL SYSTEMATIC BACTERIOLOGY 209

Bacteriales. An ordinal name suggested by Clements (1909, p. 8).
His description is as follows: "Globose, rod-like or filamentous, single
or in colonies, sometimes grouped into a loose mass (zoogloea), but never
forming pseudoplasmodia or sporangium-like masses." He recognized
five famiKes, Beggiatoaceae, Chlamydobacteriaceae, Spirillaceae, Bac-
teriaceae and Coccaceae.

Bacteridia. The Anglicized equivalent of Davaines casual name
bacteridie for the anthrax organism.

Bacteridie. A casual name given by Davaine (1863, p. 195) for the
anthrax bacillus. Used for Bacteridium q.v.

Bacteridieae. The fifth tribe of the family Bacillaceae as described
by Castellani and Chalmers (1919, p. 932). One genus only, Bacterid-
ium Schroeter, is included. The tribal designation is,

Bacillaceae growing well on ordinary laboratory media, without endospores,
and either fluorescent or chromogenic.

Type Genus. Bacteridium Schroeter, 1872.

Bacteridium. A genus proposed by Davaine (1868, p. 21) to include
organisms with filiform bodies, more or less distinctly articulated in
consequence of imperfect division, always non-motile. The name was
created to provide for the anthrax bacillus. He states,

III Genre Bacteridie. Bacteridium (Davaine). Corps filiforme, droit ou in-
flechi, plus ou moins distinctement articule, par suite d'une division spontanea
»»parfaite, toujours immobile.

Apparently in this article at least he did not give a species name. He
writes "Bacteridie Charbonneuse (Davaine)" for the anthrax bacillus.
The latin generic name is definite enough, as is also the species con-
sidered. The casual designation bacteridies was first proposed in 1863
(p. 195), in the following statement:

On voit, d'apres les considerations qui precedent, que le nom de bact^rie, par
lequel j'ai design^ primitivement ces corps, ne peut leur convenir. Lorsque
I'etude des etres microscopiques qui jouent un grand role dans la fermentation,
dans la putrefaction, etc., est a peine commencee, il serait pr^matur^ de vouloir
classer d'une maniere definitive les corpuscules du sang de rate, qui ont avec ces
€tres une analogie ^vidente. Je me bornerai done, pour designer ces corpuscules,
h, modifier l^gerement le nom que je leur ai primitivement donn6, et je les appel-
lerai d6soHBais des bacteridies.

It is apparent that we have the anomalous situation of a suitable
generic name, Bacteridium, being published, together with an adequate

210 GENERAL SYSTEMATIC BACTERIOLOGY

description of a species which should be considered the type, but without
a scientific name being given to the species. There may be some ques-
tion under such circumstances of the validityof the generic name, though
there would seem to be no statement in the International Rules of
Botanical Nomenclature which would definitely make it invalid. It
should be noted that while this author repeatedly in later writings
used the term bacteridie, the generic name Bacteridium was not em-
ployed with a specific name to designate the anthrax bacillus (1864,
p. 393), (1865, p. 334). It is of interest to note that Davaine earlier
(1863, p. 222) used the designation bacterium du sang de rate.

Schroeter (1872, p. 110) used this designation to include certain non-
motile pigment-producing bacteria, among them Bacteridium prodigo-
sum. This use of the genus name was discussed and disapproved by
Cohn (1872, p. 182) because the pigment producers have no marked
character in common with the anthrax bacillus other than lack of
motility.

Cohn says,

Wegen des Mangels der spontanen Bewegung hat Schroeter in dem voran-
stehenden Aufsatz die Kugelbacterien, welche Pigmente erzeugen, mit demsel-
ben Namen belegt, welchen Davaine fiir die unbeweglichen Stabchen des Milz-
brandblutes eingefiihrt hat (Bacteridium) . Die Milzbrandbacteridien unterschei-
den sich jedoch durchaus von den Pigmentbacterien, da sie stabchen- oder lang
fadenformig sind; sie konnen daher mit den Kugelbacterien nicht in einer Gat-
tung suzammengestellt werden, da der Mangel der Bewegung der einzige beiden
gemeinschaftliche Charakter ist.

The name was abandoned by Schroeter (1886). Mace (1897, p. 485)
makes the following comments: /

Davaine avait cru devoir distinguer autrefois un genre Bacteridium, caract^r-
ise par I'immobilite des elements a tou^ les stades de ^eur existence. II I'avait
etabli pour la Bacteridie du charbon et quelques autres observees dans I'intestin
et les infusions. Mais I'absence ou la presence de mouvements n'offre jamais de
Constance suffisante pour en faire un caract^re specifique. Un grand nombre
d'especes, tres mobiles a une certaine phase de leur existence, deviennent com- .
pletement immobiles a la periode suivante ou seulement quani les conditions de '^
vie, tout en restant bonnes, viennent k changer; beaucoup deviennent inertes,
par exemple au moment de la sporulation. Les Bacteries mobiles ne different du
reste des immobiles par aucun caractere de valeur.

Erwin F. Smith (1905, p. 158) claims that this genus name is invalid
because of the previous existence of the genus Bactridium Kunze 1817.
Whether or not this use invalidates Bacteridium Davaine depends upon

GENERAL SYSTEMATIC BACTERIOLOGY 211

the interpretation of Article 57 and Recommendation XXXI of the
botanical code. The former states that when the difference between
two names, especially two generic names, lies in the termination, these
names are to be regarded as distinct even though differing by one letter
only. The latter reads:

Many names differ by a single letter without risk of confusion. In cases where
a close approach to identity is a source of error (ex. Astrostemma and Asterosemrna
in one and the same family, Asclepiadaceae) only one, the older, of the names
should be kept in accordance with Article 51, 4°.

This last Article reads :

Every one should refuse to admit a name in the following cases:
4. When the group it designates embraces elements altogether incoherent, or
when it becomes a permanent source of confusion or error.

Smith suggested the name Aplanobacter in its place.

Vuillemin (1913, p. 519) states that lack of motility does not justify
generic recognition.

Buchanan (1918, p. 33) recognized Bacteridium as a subgenus of
Bacillus to include the non-motile species, with Bacillus (Bacteridium)
anthracis Cohn as the type.

CasteUani and Chalmers (1919, p. 933) revive the Bacteridium of
Schroeter with Bacteridium prodigiosum as the type. Their definition
(p. 958) is " Bacteridieae which are chromogenic." It constitutes the
type genus of the tribe Bacteridieae q.v. with the definition "Bacillaceae
growing well on ordinary laboratory media, without endospores, and
either fluorescent or chromogenic."

It would seem that the use of the genus Bacteridium in bacteriology
and of Bactridium in mycology is valid if organisms of which the anthrax
bacillus is the type are to be grouped into a separate genus. The previ-
ous use of Bactridium should no more invalidate Bacteridium than
Micrococca Benth. a valid genus of the Euphorbiaceae created in 1849
should invalidate Micrococcus Cohn (1872).

Bacterieae. A tribe of bacteria created by Trevisan (1879, p. 136)
with the following description :

Bacteriaceae unicellulares. Individua globulosa vel ellipsoidea vel cylindrica,
e cellula unica conflata. Sporae intra cellulam matricalem solitariae.
Multiplicatio divisione cellularum vegetativa in unam vel duos vel omnes
directiones.

212 GENERAL SYSTEMATIC BACTERIOLOGY

Two subtribes were included, namely, Eubacterieae and Sarcineae.

Buchanan (1918, p. 39) recognized this tribe as the second of the
family Bacteriaceae, with four subtribes Fusiforminae, Hemophilinae,
Rhizohiinae and Bacteriinae. The description is: "Cells rod-shaped,
never spiral nor strictly filamentous; single or in chains, motile or non-
motile, never producing endospores, either Gram-positive or -negative."

Bergey et al. (1923, p. 194) used this designation (with the spelling
Bactereae) for the sixth tribe of the family Bacteriaceae with the follow-
ing description: "Gram negative rods generally growing well on arti-
ficial media. Generally attack carbohydrates forming acid and often
gas composed of CO2 and H2. When motile, the flagella are peritrich-
ous." Six genera are included.

Bacterien. A casual name used by Cohn (1872, p. 132) and sub-
sequent German writers for the bacteria.

Bacteries. A casual name used by Davaine (1863) and subsequent
French authors for the group bacteria.

Bacteriinae. A subtribe of the tribe Bacterieae named by Buchanan
(1918, p. 47) with the following diagnosis:

Cells not fusiform, rod shaped; not hemoglobinophilic; aerobic, facultative, or
microaerophilic; not securing growth energy exclusively by the oxidation of
carbonaceous compounds. Spores never formed. Motile or non-motile.

It included the following genera: Pseudomonas, Serratia, Chromo-
bacterium, Pasteur ella, Bacterium, Proteus, Pfeifferella, Lactobacillus,
Erysipelothrix, and Corynebacterium.

Bacterina. A group created by Perty (1852, p. 179) to include the
genera Bacterium, Vibrio and Metallacter. The name has never come
into common use.

Bacteriopsis. A generic name proposed by Trevisan (1885, p. 103)
for a group of bacteria. The organisms were considered as showing
three stages of development: 1. Bacilli. 2. Filaments. 3. Cocci.
The bacillus form was regarded as most typical. The cells were short
cylindrical or ellipsoid, straight, not articulate, colorless or colored,
showing both macrobacilli and microbacilli; cytoplasm equally diffused
in cells. Spores none or unknown.

The species included in the genus are as follows :

Bacteriopsis Rasmusseni = Leptothrix I Rasmussen.
Bacteriopsis aceti = Mycoderma aceti Pasteur.
Bacteriopsis Pasieuriana = Bact. Pasteurianum E. Chr. Hansen.
Bacteriopsis merismopedioides = Bact. merismopedioides Zopf.

GENERAL SYSTEMATIC BACTERIOLOGY 213

Bacteriopsis ureae = Micrococcus ureae Zopf.
Bacteriopsis ianthina = Bad. ianthinum Zopf.
Bacteriopsis synxantha = Vibrio synxanthus Ehrenb.

Bacteriopsis ovata = Panhistophyton ovatum Lebert.

The genus has not been used by subsequent authors, and is not even
recognized by DeToni and Trevisan (1889).

It is rejected by Erwin F. Smith (1905, p. 174).

Probably the first named species, Bacteriopsis Rasmusseni, should be
regarded as the type. It was later (1889, p. 930) placed by De Toni and
Trevisan in the genus Rasmussenia (the fourth species, R. anceps). If
no older generic name for the mouth leptothrix forms can be found, this
would probably be a valid designation for them. It may be regarded
as a synonym of Leptotrichia.

Bacterium. A generic name proposed by Ehrenberg (1828, p. 8).
His diagnosis is as follows:

Bacterium, Novum Genus, Familia Vibrionorum. Character Generis: Cor-
pus polygastricum? anenterum? nudum, oblongum, fusiforme aut filiforme,
rectum, monomorphum (contractione nunquam dilatatum), parum flexile (nee
aperte undatum), transverse in multas partes sponte dividuum.

The only species described was Bacterium triloculare The descrip-
tion was as follows:

B. triloculare nov. spec; distincte triloculare s. triarticulatum, subfusi-
formum, hyalinum.

Animalculum 1 300 lineae longum, corpore tereti. Articuli s. septa interna
divisionem instantem multiplicem transversam indicare videntur. Mobile sed
pigrum animalculum.

In Oasi Jovis Hammonis Siwae observatum, praeterea nullibi.

Bacterii Generis physiologia huiusque obscurra. Cibo colorato Ventriculos
replere hae formae respuunt ideoque ad Polygastrica non misi dubitanter et
interim coUocantur.

While it is not improbable that Ehrenberg actually described one of
the organisms now included with the bacteria, it is evident that there is
nothing in the description which would make probable a modern identi-
fication of the species.

Two years later Ehrenberg (1830, p. 38) included some eleven species
in his Bacterium. It is to be noted that some were not new species.
Several of Mueller's species of infusoria described in 1783 were included,
among them being Bacterium {Monas) termo (Mueller) Ehrenberg. In
the previous (1828) paper, Ehrenberg had recognized Monas termo

214 GENERAL SYSTEMATIC BACTERIOLOGY

Mueller as distinct, not including it in the genus Bacterium. Inasmuch
as Bacterium termo has been much discussed in the literature, the descrip-
tion given by Mueller (1786, p. 1) should be noted.

Monas termo. Animalculum omnium, quae microscopium simplex offert,
minimum simplicissimum, punctulum, gelatinosae, substantiae pisum micro-
scopium composirum eludere videtur, dum ne quidem sub hoc distinctius
appareat.

Sphaericum, an orbiculare? baud video.

Guttula aquae, in qua maceratio facta est, his corpusculis adeo saepe repletur,
et ne mimimum vacuum distingui liceat, ipsamque aque substantium in aliam
minus hyalinam, globularem ex punctis consertissimis, omnem calculum super-
antibus mutatam crederes.

In hac massa motus, qualem radii solares in aqua micantes eflSngere solent,
oculis exhibetur, dum animalcula, examinis opum instar, vehementer com-
moventur.

In infusione vegetabilium et animalium. Huius guttula jam intra vigenti
quatuor boras conspicitur quasi massa globularis, aut nuUus in ea motus nee odor
percepitur, brevi vero motus seu fermentatio cum foetore interabili insequi-
tur, at non in omni.

Fig. 1. Guttulam aquae fluvialis Monade Ter?none scetentam valde auctam
exhibet.

Ehrenberg's description of Monas termo Mueller as given in 1828 is
also pertinent.

M. Termo (Mueller) : 1/1664 ad 1/500 linea crassa, exacte blobosa, hyalina.

Specimena, seu potius Myriades, quas Siwae in Oasi libyca vidi et iliac, quas
infuso Pipere nigro in Arabia accepi, magnitudine 1/1664 lineae fere aequabant.
Quae e sinaitica valle Wadi Esle depromsi mensuram 1/1660 lineae offerebant.
Berolini et in Sibiria interdum maiora individua, ab eadem specie vix segreganda,
vidi, maxima 1/500 lineae crassa, quae, si divisione spontanea funduntur, in partes
1/1000 lineae crassas, reliquis similes, abeunt.

Monadum speciales characteres, ob microscopiorum, quae vocamus, sufficien-
ter eas augendi vim deficientem, praeter corporis formam et mensuram, nonhabent
quo nitantur et firmitate physiologia saepe carent. Motus, coloris, mensurae et
propagationis ratio cum forma nonnuUas quidem species bene destinguere sunt,
in aliis characterum gravitas desideratur, sed formarum magnam copiam in aquis
vagari unusquisque, qui his animalculis studium impendit, facile sibi persuadet.
Quin ex Monadibus, Vibrionibus, Bacteriis et Bodonibus iis, quae minutie excel-
lunt et cibos colaratos respuunt, novae animalium classis vestigia posteris pre-
menda enitescere saepe mihi visa sunt.

The generic description given for Bacterium by Ehrenberg (1830,
p. 38) is: "Bacterium. Nov. Gen. Haec genera, Oscillatoriis valde
affinia ore nutriri nundum vidi." Eleven species are listed.

Two years later (Ehrenberg 1832) differentiated six species of the
genus Bacterium. Two of these, Bact. articulatum and Bad. triloculare

GENERAL SYSTEMATIC BACTERIOLOGY 215

are definitely included. Four other species Bad. Enchelys, Bad.
pundum, Bad. tremulans and Bad. termo are questioned,

SLx years later in his classic work on the Infusoria Ehrenberg (1836, .
p. 75) characterized the genus Baderium as follows: "Animal e familia
Vibrioniorum, divisione spontanea in catenam filiformen rigidulam
abiens."

One species only, Baderium triloculare is included. In his drawing of
Baderium triloculare a polar flagellum is shown.

A careful perusal of the description certainly reveals nothing that
would enable one even with a moderate degree of certainty to identify
Ehrenberg's species. Certainly most of them were based on impure or
mixed cultures. From different localities and conditions the same organ-
ism was frequently described though differing sufficiently in size and
appearance to justify the conclusion that the forms were quite distinct.

Inasmuch as some effort has been made to tie up the genus Baderium
to Baderium termo as a type species, the following points are worth}^ of
note.

1 . Bacterium termo (Mueller) Ehrenberg was not included as a mem-
ber of the Genus Baderium in the paper in which the genus was first
proposed, in fact, as Monas termo Mueller, it was placed in another
genus.

2. Mueller (1786, p. 1) states that Monas termo is spherical and Ehr-
enberg (1828) likewise describes it as globular ("exacte globosa")-

3. The organism was found in water and in infusions of animal and
vegetable matter.

It should be noted that Ehrenberg includes the genus Bacterium as
one of five genera in his family Vibrionia, the other genera being Vibrio,
Spirochaeta, Spirillum and Spirodiscus. Bacterium is differentiated
from Vibrio in that it is non-flexuous, while the latter is flexuous.

Dujardin (1841, p. 212) practically adopted Ehrenberg's classifica-
tion. He designated as Bacterium all those forms which are straight,
more or less definitely jointed, non-flexile, and which were capable of
only a slow wave-like motion. Vibrio, on the other hand, contained
those organisms which are straight or bent, more or less definitely
jointed, and which show sinuous motion like a snake. He placed three
species in this genus. Bad. termo, Bad. catenula, and Bad. pundum.
His description reads: "Corps fihforme, roide, devenant plus ou moins
distinctement articule par suite d'une division spontanee imparfaite.
Mouvement vacillant non ondulatoire." Here again there is nothing
which will enable the bacteriologist to identify any one of the species.

216 GENERAL SYSTEMATIC BACTERIOLOGY

It is of interest to note that many subsequent writers ascribe the
species Bacterium termo to Dujardin.

Diesing (1850, p. 14) gives the following generic description of
Bacterium.

Corpus nudum, lorica destitutum head mutabile, cylindricum subovatum aut
subglobosum, partitione imperfecta uniseriali, multiplici, transversa in synther-
ium lineare, moniliforme, rigidulum, rectum, hyalinum accrescens. Flagellum
in articulo primo terminale simplex. Ocellus nuUus.

Perty (1852, p. 179) developed a classification of the infusoria, recog-
nizing a family Vibrionida with two subfamilies Spirillina and Bac-
terina. Under the latter the genera Vibrio, Bacterium, Metallacter
and Sporone^na are included. Vibrio is defined as flexuous. Bacterium
is non-flexuous. The only species of Bacterium described is Bact.
termo ascribed to Dujardin. It is recorded as occurring "in den aller-
verschiedensten faulenden Aufglissen und Sumpfwassern das ganze
Jahr." He notes that it was recorded by Dujardin "im Eiter und an-
dern pathologischen Fliissigkeiten" and even "nach Leeuwenhoek im
Zahnschleim." The description is wholly unsatisfactory, and shows a
tendency, which became more pronounced during the succeeding two
decades, to call all organisms associated with putrefaction and decay
Bacterium termo.

Cohn (1854, p. 123) for the first time definitely grouped the form now
termed bacteria under the plant kingdom, removing them from the
Infusoria. He studied at length the Bacterium termo Dujardin, which
he regarded as a synonym of Vibrio lineola Ehrenberg, He concluded
this form to represent merely the swarm cell state of an alga-like fungus.
He was unable to see the "cilia." He gave it the generic name Zoogloea
with the following characters:

Cellulae minimae, bacilliformes, hyalinae, gelatina hyalina in masses mucosas
globosas, uvaeformes, mox membranaceas consociatae, dein singulae elapsae,
per aquam vacillantes.

The species became Zoogloea termo. As synonyms he notes "Pal-
mella infusionum Ehr., Micraloa teres V. Flotow, Bacterium termo
Dujardin and Vibrio lineola Ehrenberg.

Several authors in the next two decades followed Cohn in the sub-
stitution of Zoogloea for Bacterium. For example, Rabenhorst (1865,
p. 35) in his "Flora Europaea Algarum" includes this genus among the
algae under the heading "Formae achroae, hyalinae {mea sententia ad

GENERAL SYSTEMATIC BACTERIOLOGY 217

fungos referendae") . The generic description given is identical with
that of Cohn. The single species Zoogloea termo (Miiller) Cohn is
briefly described as : "Z. thallo gelatinoso globoso, cellulis liberis mobili-
bus, rectis, 1/2000-1/700" aequantibus. Hab. in aquis stagnantibus,
imprimis corruptis ubique."

A Zoogloea ramigera was later described by Itzigsohn (1867, p. 414).

The next author of note defining Bacterium was Davaine (1864,
p. 629) who, like Cohn, separated the Vihriones from the protozoa,
and described the genera Bacterium, Vibrio and Spirillum. His defini-
tion of Bacterium (given in 1868, p. 68) is identical with that of Dujar-
din. It should be noted that this author emphasized the importance
of motility in the generic diagnosis.

An interesting sidelight on the utilization at this time of the term
Bacterium termo to include the greatest variety of microorganisms is to
be found in the writings of Liiders (1866, p. 36) who concluded that this
wide spread organism was a growth stage of a fungus. Hallier (1886)
introduced and developed his theory of pleomorphism which reached
its culmination in the work of Billroth (1874). This led to general dis-
trust at this time in the existence of true bacterial species and indi-
rectly contributed to the lack of regard for the rules of nomenclature
during the next several decades.

Davaine (1868, p. 21) used the name in the sense of Dujardin. differ-
entiating the non-motile forms such as the anthrax bacillus in the new
genus Bacteridium. His description of Bacterium is as follows:

Genre Bacterie. Bacterium (Ehrenberg, Dujardin). Corps filiforme, roide,
devenant plus ou moins distinctement artieule par suite d'une division spontanee
imparfaite; mouvement vacillant, non ondulatoire (Dujardin).

In summary, to the year 1872, the generic name Bacterium was not
applied to any species which can now be recognized satisfactorily. The
original Bacterium triloculare Ehrenberg was no longer recognized in
the literature. Bacterium, termo the organism found commonly in
putrefying solutions was the only species.

Cohn (1872, p. 167) rather radically emended the previous generic
descriptions of Bacterium to include those rod-shaped organisms in
which the cells are short, never filamentous. He made it the sole repre-
sentative of his tribe Microbacteria. The cells are short cylindric
or elliptical, never in chains or filaments, often forming firm zooglocal
masses, alternating motile with non-motile stages. His description was
largely based on his conception of Bacterium termo, which he regarded

218 GENERAL SYSTEMATIC BACTERIOLOGY

as the principal agency of decay, ("ohne Bacterium termo keine
Faulniss")- He described the reaction secured by inoculating the
bacteria from putrefying beans into his ammonium tartrate solution
and noted the development therein of a green fluorescence.

Should this description of Cohn be used as fixing the type for Bac-
terium as Bacterium termo? The following objections may be raised:

1. Unquestionably Cohn was dealing with impure or mixed cultures.
The fact that when this mixture was inoculated into Cohn's nutrient
solution a green fluorescence was produced by no means flxes this as
a characteristic of Bacterium termo. Bacteria capable of bringing about
this change are widely distributed in nature. In other words, in the
heterogeneous mass of organisms present in infusions, known as
Bacterium termo, there are included certain fluorescent bacteria capable
of growing in Cohn's nutrient solution. The International Botanical
Code is explicit on this point :

Article 51. Every one should refuse to admit a name in the following cases:
4. When the group which it designates embraces elements altogether inco-
herent or when it becomes a permanent source of confusion or error.

2. The species Bacterium termo was first described as Monas tertno
Mueller, it was tentatively transferred to the genus Bacterium by Ehren-
berg, but later rejected by him, and first definitely included in the genus
by Dujardin. It was later made a type of the genus Zoogloea by Cohn.
Inasmuch as this organism was not at first included in the genus Bac-
terium, in fact was definitely excluded by the author of the name, it
does not seem advisable to accept it as the type.

Schroeter (1872, p. 120) put in the genus Bacterium three species
of bacteria which had previously been described in other genera, the
Vibrio synxanthus^ Ehrenberg (1840, p. 202) he renamed Bacterium
synxanthum (the spore bearing rod responsible for yellow milk), the
Vibrio syncyaneus Ehrenberg^ (1840, p. 202) he termed Bacterium
syncyaneum (the polar flagellate organism of blue milk) and named the
Bacterium aeruginosum, the polar flagellate organism of blue green pus.
Both of these organisms were later (1886, p. 157) transferred by Schroe-
ter to the genus Bacillus. The names used by Schroeter were accepted
by Cohn (1872b, p. 173).

Should one of Schroeter's species be accepted as the generic type?
It probably would be inadvisable to designate thus either of the species

1 The Vibrio xanthogenus, Fuchs (1841, p. 193).
" The Vibrio cyanogenus, Fuchs (1841, p. 190).

GENERAL SYSTEMATIC BACTERIOLOGY 219

transferred to this genus from other genera, for it is quite conceivable,
that inasmuch as Vibrio syncyaneus Ehrenberg was probably the first
species of Vibrio sufficient^ described so that it can be certainty recog-
nized and identified today, it might be designated as the type of Vibrio.
In other words, if it is to be accepted as a type, it should be for Vibrio and
not for Bacterium. The form from yellow milk quite certainly should be
placed in the genus Bacillus. Bacterium aeruginosum is so closely rela-
ted to Bact. syncyanewn that they probably should be placed in the
same genus. It would certainly be unwise to choose the former as the
type, as there might well be question as to whether it did not belong
likewise in the genus Vibrio. It would seem that stability of nomen-
clature would not be conserved by the choice of any one of these as a
type species.

If Bacterium is to be retained as a bacterial genus, it seems necessary
to pick the type species from those described subsequently to 1872.

Lister (1873, p. 408) gave the name Bacteriuin lactis to an organism
responsible for lactic acid fermentation. "While his description may not
be sufficiently accurate to enable us to determine with certainty whether
he described the lactic streptococcus or one of the aerogenic lactic
bacilli, (such as Bacterium aerogenes) now generally regarded as
belonging to the colon-typhoid group, it is probable that the former
should be the interpretation. Bacterium lactis became Streptococcus
lactis and is not available as a type.

Lankester (1873, p. 13) described a "peach coloured Bacterium"
from water under the name Bacterium rubescens. The description makes
it evident that he was working with organisms belonging to the group
of forms containing bacteriopurpurin, that is, to the group of sulfur
bacteria. The description further makes it evident that he was not
dealing with a pure culture. He dilates upon its variability, the appear-
ance of rods and spirals, and motile and non-motile cells, etc. Certain
of the forms were quite certainly previously described under other
names. Cohn wrote Lankester (1874, p. 399) that his organism was
the Monas Okeni Ehrenberg, the Clathrocystis roseopersicina of Cohn.
While Lankester combated Cohn's statements, modern knowledge
of the group would seem to justify them. Certainty the recog-
nition of Bacterium rubescens as a type species would be unwise.

Warming (1875) described several species of Bacterium from the
water on the coast of Denmark. These were Bacterium griseum, Bact.
litoreum, and Bact. fusiforme. They were not grown in pure cultures
and apparently are not identifiable with certainty.

220 GENERAL SYSTEMATIC BACTERIOLOGY

Dallinger (1878, p. 159) studied Bacterium termo microscopically,
demonstrating motility to be due to a terminal flagellum. It is defined
in the sense of Cohn.

In 1875 Cohn included the genus in the tribe Glaeogenae. It was
defined as having cylindrical cells, without phycochrome, very small,
cells united in glairy families, amorphous when in repose, or entirely
free, never disposed in filaments. In this revision he accredited the
genus to Dujardin rather than to Ehrenberg. Magnin (1878, p. 80)
follows Cohn exactly. The diagnosis reads :

Bacterium, Duj. emend. Cells cylindrical or elliptical, free or united in pairs
during their division, rarely in fours, never in chains, sometimes in zoogloeae,
having spontaneous movements, oscillatory and very active, especially in media
rich in alimentary material and in presence of oxygen.

The species are divided into three groups:

1. The bacteria of putrefaction (Bad. termo Ehr. and Bad. lineola
Cohn).

2. The bacteria of lactic and acetic fermentations, and

3. The chromogenic bacteria (including Bad. xanthinum Schroter,
Bact. syncyaneum Schroter, Bad. aeruginosum Schroter, and Bad.
brunneum Schroter).

Of the species, the chromogenic forms can for the most part still
be readily recognized.

Lanzi (1876, p. 256) designated the organism responsible for acetic
fermentation Bacterium aceti.

Trevisan (1879, p. 136) gives the following synonymy and description:

Bacterium Ehrenb. (1830 non 1828) emend Cohn (Beitr. I Heft 2, p. 177);
(Chromatium Perty 1852; Zoogloea Cohn 1853; Rhabdomonas, Cohn 1875). Cel-
lulae breviter cylindricae, vel ellipsoideae, vel fusiformes. Multiplicatio divisione
cellularum vegetativa semper ad eandem directionem longitudialem.

The species recognized are Bad. aceti Lanzi 1876, Bad. termo Ehrenb.,
Bad. lineola Cohn, Bad. tremulans Trevisan, Bad. catenula Dujard.,
Bad. pundum Ehrenb., Bact. synxanthum Schroeter, Bad. syncyaneum
Schroeter and Bact. aeruginosum Cohn.

The generic description of Bacterium by Luerrsen (1879, p. 20) does
not assist in fixing a type species.

Van Tieghem (1879) described a Bacterium lucens from the surface
of liquids.

Sternberg (1880, p. 80) in his translation of Magnin's (1878) text on
the bacteria gives the following characterization of the genus Bacterium :

GENERAL SYSTEMATIC BACTERIOLOGY 221

Cells cylindrical or elliptical, free or united in pairs during their division^
rarely in fours, never in chains (Leptothrix or Torula), sometimes in zoogloea
(differing from the zoogloea of spherical bacteria by a more abundant and firmer
intercellular substance), having spontaneous movements, oscillatory and very
active, especially in media rich in alimentary material and in presence of oxygen.

He includes descriptions only of species which have already been
noted. The}' are separated into three groups, the bacteria of putre-
faction, those causing lactic and acetic fermentation, and the chromo-
genic forms.

Thin (1880) described a Bacterium foetidum from malodorous per-
spiration. The culture methods used did not insure pure cultures.

Winter (1880, p. 51) characterizes Bacterium (which he ascribes to
Cohn) as follows :

Zellen kurz cylindrisch, lang elliptisch oder spindelformig, durch Quertheil-
ung sich vermehrend, spontan beweglich. Die Tochterzellen trennen sich
entweder bald nach der Theilung von einander oder bleiben zu 2 bis mehr ketten-
artig vereinigt. Auch Zoogloea-Bildung ist haufig. Sporenbildung ahnlich wie
bei Bacillus.

He lists and describes eight species, none new. It will be noted that
he includes for the first time the possibility of spore formation as a
character of the genus.

Van Tieghem (1881) described a green organism from rain water
which had collected in the pileus of a Polyporus, giving it the name
Bacterium viride.

Thin (1881) also described a Bacterium decalvans from alopecia
areata.

Zopf (1883, p. 48) materially modified the definition of the genus fol-
lowing the conception of pleomorphism, to include those organisms show-
ing four growth forms, cocci, short rods, long rods and filaments, the
latter never with differentiation of base and tip. The following year
(1884, p. 45) he used the same definition. He included in the genus
some seventeen species, most of which are still recognized. Organisms
previously described by other authors as in the genus Bacillus are
included, such as Bacterium tuberculosis, Bad. typhosum, Bact. subtile
and Bact. anihracis. His Bact. ianthinum was the Bacteridium viola-
ceum of Schroeter and the Chromobacterium violaceum of Bergonzini.
The only organism apparently newly named and placed in this genus
was Bacterium acidi-lactici. The description is scarcely adequate to
identify this organism as the one now generally recognized under this
name. The specific name acidi-lactici has been used in so many senses

222 GENERAL SYSTEMATIC BACTERIOLOGY

by subsequent authors as to make identification difficult. However,
Bad. acidi-lactici may be regarded as a possible type species.

Engelmann (1882, p. 94) described an organism from water as Bac-
terium photometricum. It was insufficiently differentiated.

Kurth (1883, p. 97) isolated and described from the alimentary tract
of the domestic fowl an organism which he named Bacterium Zopfii.
This organism is adequately known at the present time.

Lanzi (1883, abs. 1884, p. 786) described an organism as Bacterium
morhilli but not adequately.

Luerssen (1879, p. 20) used the generic diagnosis of Cohn as did also
Grove (1884, p. 22). This latter author lists five colorless species
(including Bact. termo) and four chromogenic species (including Bact.
synxanthum Schroter, Bact. syncyaneum Schroter, Bact. aeruginosum
Schroter and Bact. violaceum (Bergonzini) Grove). The chromogenic
species may all be recognized.

Van Tieghem (1884, p. 1110) defined Bacterium as containing rod-
shaped cells, separating as soon as formed, never in filaments, never
spiral. He regarded the name more as a form genus than a natural
genus.

Escherich (1885) described two organisms, Bacterium coli commune
and Bacterium lactis aerogenes, from infant stools. The description
was greatly expanded the next year (1886, pp. 57 and 63) . These organ-
isms have been consistently known by these names to the present time.

In 1885 Trelease described several new species of pigmented bacteria
under the names Bacterium candidum, Bact. luteum, Bact. aurantiacum,
Bact. chlorinum and Bact. incarnatum. Zukal (1885) studied the mor-
phology of a Bacterium tortuosum from water.

Zopf in 1885 (p. 61) completely revised his classification. Bacterium
is defined as made up of those species which exist as cocci and rods, or
the latter only, united into filaments, spore formation lacking or un-
known. It will be noted that here the emphasis is changed to absence
of spores. Hueppe (1885) used practically the same diagnosis. Maggi
(1886, p. 84) listed five species of this genus.

Fltigge (1886) outlined a classification of bacteria which has been
extensively followed by medical bacteriologists. His genus Bacterium
is defined to include cylindric forms, short, single or loosely united or in
amorphous slimy masses.

Schroter (1886, p. 155) states that the genus Bacterium is not well
characterized and possibly should be united with the genus Bacillus
from which it is separated with difficulty. He accepts absence of spores

GENERAL SYSTEMATIC BACTERIOLOGY 223

as a generic character, and states that the vegetative cells are short
rods, little longer than broad, in the rounded form either solitary or
embedded in slime (Zoogloea), from which a motile form emerges.
Three species only are listed: Bad. termo Ehr., Bact. septichaemiae
and Bact. ckolerae gallinarum. The chromogenic species previously
listed here by Cohn and Schroter are transferred to the genus Bacillus.
Hansgirg (1888, p. 265) Hsted Bacterium as the second genus of the sub-
family Microbacteria, but with no diagnosis. De Toni and Trevisan
(1889, p. 1020) give the following generic diagnosis:

Bacterium Ehrenb. (1830) emend. Trev. Bacterii et Bacilli species Auctorum.
Baculi vulgo brevis, interdum brevissimi, ut plurimum ellipsoidei, raro cylin-
dracei, apicibus obtusis, recti. Sporae (arthrosporae) globosae, e coccorum
metamorphosi ortae.

The genus is included in the subfamily Baculogenae and the tribe
Bacilleae. In all, thirty-four species are described. Of these Bact.
aceti (Kuetz) Lanzi, Bact. Pasteurianum (Hanson) Zopf, Bact. allan-
toides Trev. and Bact. Balhianii Billet are noted as particularly typical.
The genus is divided into two primary groups, Bacteria achroa (22
species) and Bacteria chromogena (12 species). The first group is again
sub-divided into Species Zymogena (8 species, mostly acetic acid bac-
teria), Species saprophyticae (13 species) and Species anthrophobiae (1
species). The second group is divided into Species granula sulphuris
nulla secernentes (7 species) and Species granula sulphuris secernentes
(5 species). Baumgarten (1890) abandoned the genus, including all rod
forms in Bacillus. Billet (1890), p. 23) s^ys "Formes rectilignes Bac-
terium, element 1 a 5 fois plus long que large." Sternberg (1892, p. 18)
states: "This genus, established by Dujardin, is now generally aban-
doned, the species formerly included in it being transferred to the genus
Bacillus." Ludwig (1892) included in Bacterium rod-shaped elliptical
organisms, not in long filaments, not embedded in slime, and differen-
tiated from Bacillus by lack of endogenous spores. Freudenreich (1894)
defines a Bacterium as a rod without endospores or with arthrospores.

Migula (1894, p. 236) radically emended the genus to include only the
non-motile rods, i.e., those forms with shorter or longer cylindric cells,
sometimes forming filaments, without flagella, endospore formation ob-
served in many species, in others apparently completely lacking. He
states: *' Bacterium Cohn.ZeUen ohne Bewegungsorgane oft mit Endo-
sporenbildung. (Z. B. Bacterium Anthracis)." He notes that about
200 species are known.

224 GENERAL SYSTEMATIC BACTERIOLOGY

Clements (1894, p. 27) defined the genus Bacterium as follows: "Cells
very short, ellipsoid, rarely cylindrical, motile or non-motile, often
imbedded in a gelatinous matrix and forming zoogloea."

Two species only are described. Bacterium termo and Bact. aceti.

The genus name Bacterium is not used by Fischer (1895) at all. Leh-
mann and Neumann (1896, p. 181) emphasized lack of endospores as the
most important character. They say

Zellen mindestens l\ mal. meist aber 2-6 mal als lang als breit, gerade oder in
einer Ebene gekrummt, zuweilen lange echte oder Scheinfaden bildend, mit oder
ohne Geisseln. Stets ohne Endospores, fiir einzelne Arten sind Arthrosporen
beschrieben.

Mace (1897) retained the older conception of the genus. He states:

La longeur relative etait le seul caract^re qui le distingerait du genre Bac-
terium. Nous Savons que ce caract^re ne peut etre consid^re comme absolu,
mais qui varie au contraire dans des limites tres larges, pour des conditions de
vie qui peuvent etre considere^s comme normales.

Migula in 1897 again discusses the importance of organs of motility
in a system of classification, and once more defined the genus as consist-
ing of non-motile rods. Chester in his Manual (1901, p. 117) adopts
Migula's definition of Bacterium, as does also Allan J. Smith (1902, p.
270) and Kendall (1902, p. 484).

Klocker (1903, p. 332) evades the issue by using the generic name given
by the author of the specific name of the species under discussion. He
states "For distinguishing purposes the spore formation and the flagella
have been suggested, but these characteristics have proved to be
insufficient."

Matzuschita (1902, p. IV) does not use the genus name Bacterium.

Schmidt and Weis (1902, p. 294) define the genus as follows:

Die Zellen sind cylindrisch, stabformig, frei oder zu Faden verbunden. Geis-
seln fehlen stets, und diese Arten sind daher zu keiner Zeit ihres Lebens beweg-
lich. Endosporenbildung bei vielen bekannt. Zur Gattung Bacterium gehort
eine sehr grosse Anzahl (iiber 300) Arten, von denen viele pathogen sind.

Erwin F. Smith (1905, p. 160) discusses at considerable length the
history of the generic name Bacterium. He comes to the conclusion
that Bact. termo of Cohn can be identified with sufficient accuracy as a
green fluorescent organism with polar flagella, developing in Cohn's
nutrient solution when inoculated with beans. He, therefore, formu-
lates the following diagnosis :

GENERAL SYSTEMATIC BACTERIOLOGY 225

Bacterium Cohn. Type : The one-flagellate, green fluorescent schizomycetes,
capable of growing in Cohn's nutrient solution. To these should be added all
the morphologically similar non-fluorescent and yellow species. Synonym:
Pseudomonas Migula.

He creates the new genus Aplanobacter to replace the genus Bacterium
of Migula.

Fliigge (1908) includes in the genus all rods which develop no spores.
He divides the genus into nine groups which are worthy of careful con-
sideration as generic groups.

ElHs (1909, p. 6) follows Migula.

Orla-Jensen (1909, p. 344) places the genus Bacterium in his family
Acidohacteriaceae, the type species being Bact. coli.

Conn (1909, p. 12) defines Bacterium as a non-motile rod, contrasting
Bacillus which is defined as a motile rod. Heim (1911, p. 25) uses
Bacterium as a subhead under Bacillus to include non-spore-bearing
forms.

Frost (1911, p. 57) follows Migula exactly. Schneider (1912, p. 23)
includes "the old genus Bacterium in the genus Bacillus." Meyer
(1912, p. 2) uses Bacterium as a section of the genus Bacillus including
those forms whose fiagella are unknown.

Lohnis (1913, p. 45) differentiates Bacillus and Bacterium on the basis
of endospore production.

Vuillemin (1913, p. 524) advocates the designation of Bacterium as a
Genus conservandum with a prototype Bacterium termo Ehr. and specific
tj^pe Bacterium pyocyaneum. This, it will be remembered, is practically
the recommendation of E. F. Smith. VuiUemin states that Ehrenberg
differentiated Bacterium from other types of Schizomycetes by its oscillat-
ing movement. Today, he states, we know this type of motion to be
due to two morphological characters, short rods and polar fiagella.
Bact. pyocyaneum is a short rod with polar fiagella, hence the designation
of this species as the type.

Winslow et al. (Committee Society of American Bacteriologists (1917,
p. 561)) adopted the view of Orla-Jensen and gave the following generic
definition :

Motile or non-motile rods, staining evenly. Easily cultivable. Animal
pathogens or saprophytes. Often chromogenic. Many forms decompose
carbohydrates.

The type species is Bacterium coli Escherich.

Buchanan (1918, p. 53) has likewise followed Orla-Jensen with the
definition:

226 GENERAL SYSTEMATIC BACTERIOLOGY

Plump rods, without spores, Gram-negative, motile by means of peritrichous
flagella, or non-motile, liquefying gelatin very slowly or not at all. Usually show-
ing marked power to ferment carbohydrates, frequentlj'^ with gas production.

The type species is Bacterium coli Escherich.

The genus is a large one, including many species. It is generally divided into
subgroups based primarily upon the fermentative reactions. It may be conven-
ient to recognize these as subgenera separated from each other by the charac-
teristics noted in the following key:

Key to the subgenera of Bacterium

A. Organisms which show a maximum of fermentative power, including fermenta-
tion of lactose, rarely pathogenic, some forms slowly liquefy gelatin.

Subgenus 1. Aerohacter (or Eu-Bacterium) .

B. Organisms not showing maximum fermentative power, never producing gas
in lactose, frequently pathogenic, never liquefying gelatin.

1. Producing acid and gas from glucose, sometimes other sugars, but not

from lactose Subgenus 2. Salmonella.

2. Producing gas from none of the carbohydrates, acid sometimes

formed Subgenus 3. Eberthella.

Breed, Conn and Baker (1918, p. 445) suggest that the name be
dropped, or at most regarded as a general designation for insufficient!}^
described organisms,

Winslow et al. (1920, p. 211) in the final report of the Committee use
the following definition :

Gram-negative, evenly staining rods. Often motile, with peritrichic flagella.
Easily cultivable, forming grape-vine leaf or convex whitish surface colonies.
Liquefy gelatin rarely. All forms except B. alcaligenes and the B. abortus group
attack the hexoses and most species ferment a large series of carbohydrates.
Acid formed by all, gas (CO2 and H2) only by one series. Typically intestinal
parasites of man and the higher animals although several species may occur on
plants and one (B. aerogenes) is widely distributed in nature. Many species
pathogenic.

Type species, B. coli Escherich 1885, p. 518.

Castellani and Chalmers (1919) have broken up the genus Bacterium
into a large number of genera, apparently dropping this generic name
entirely. In this they have been followed by Bergey et al. (1923).

It is evident from the preceding analysis of the important literature
bearing on the subject that the various diagnoses of the genus Bacterium
with their principal advocates may be grouped as follows:

1. Pre-Cohnian conceptions. Relatively rigid cells or chains of cells,
not flexible, motile, oscillating. First species described Bacterium trilo-
culare'Ehr. No type species designated. No species described at pres-

GENERAL SYSTEMATIC BACTERIOLOGY 227

ent recognizable with certainty. Ehrenberg (1828, 1830, 1836), Dujar-
din (1841), Perty (1852), Cohn (1854), Davaine (1864), Luders (1866),
Davaine (1868).

2. Cohnian conception. Short cyHndric or elliptic cells, never in
chains or filaments. Alternating motility and non-motility. Shape
and grouping the primary characteristics. No definite designation of
a type species, although in the earlier writings Bacterium termo is fre-
quently mentioned. Cohn (1872, 1875), Lister (1873), Lankester
(1873), DaUinger and Drysdale (1874), Magnin (1878), Winter (1879),
Luerssen (1879), Trevisan (1879), Grove (1884), Van Tieghem (1884),
Escherich (1885), Fliigge (1886).

3. Zopfian conception. Rod shap