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Los Angeles Cal.

A SYNOPSIS

BACTERIA AND YEAST FUNGI

A SYNOPSIS

OF THE

BACTERIA AND YEAST FUNGI

AND ALLIED SPECIES
(SCHIZOMYCETES AND SACCHAROMYCETES)

BY W. B. GROVE, B.A.

MICROSCOPICAL SOCI

WITH EIGHTY-SEVEN ILLUSTRATIONS

Hontion

CHATTO AND WINDUS, PICCADILLY
1884

[All rights reserved}

PREFACE.

THE aim of this little work is almost purely morpho-
logical ; physiological details are only occasionally
introduced. The two first chapters are translated,
with additions, the more important of which are in-
dicated by square brackets [ ], from Dr. G. Winter's
edition of " Die Pilze," in Rabenhorst's " Kryptoga-
men-Flora," by kind permission of the author. With
a view to increase its usefulness, I have added to the
few figures there given a considerable number drawn
from various sources, in many cases from the original
authorities, and a few of my own. I must acknow-
ledge my indebtedness, for help of various kinds, to
Dr. Winter, and also to Dr. John Anthony, of Bir-
mingham, and Mr. James Britten ; and, in addition,
to the " Summary of Current Researches," in the
Journal of the Royal Microscopical Society, as a guide
to the literature of the subject.

W. B. GROVE.

BIRMINGHAM,

May ist, 1884.

CONTENTS.

CHAPTER * PAGE

I. SCHIZOMYCETES ... ... ... ... I

II. SACCHAROMYCETES ... ... ... ... 57

III. CLASSIFICATION ... ... ... ... ... 68

IV. PROTEAN AND LITTLE-KNOWN SPECIES ... 83

APPENDIX A. ON THE UNIT OF MICROSCOPICAL MEASURE-
MENT ... ... ... ... 101

„ B. ON THE STAINING OF "BACILLUS TUBERCULOSIS" 103

,, C. DISEASES PRODUCED BY THE SCHIZOMYCETES 105

INDEX ... ... ... ... ... ... ... 107

SYNOPSIS OF THE BACTERIA
AND YEAST FUNGI.

CHAPTER I.

SCHIZOMYCETES.

The Schizomycetes, or "splitting-fungi (Spaltpihe), are

unicellular plants, ^which multiply by repeated subdivision in

one, two, or three dimensions of space, and also frequently

reproduce themselves by spores, which are formed endogenously.

They live, either isolated or combined in various ways, in

fluids and in living or dead organisms, in which they produce

decompositions and fermentations, but never alcoholic fermen-

s tat ion.

The Schizomycetes are one of the most difficult and
least-known classes of Fungi. In the first place, it is doubt-
ful whether they are to be reckoned among the Fungi or not.
Cohn unites them with the Phycochromacese, which are
usually considered to be Algse, and includes both groups
under the name of Schizophytse. I cannot agree to this
union. With respect to morphological relations, indeed, the
Schizomycetes are in many ways exceedingly like the
Phycochromacese ; but their physiological relations are quite

2 Synopsis of the Bacteria and Yeast Fungi.

different The latter live, like all Algae, in pure water, which
contains comparatively little organic matter ; or they are
found on dripping rocks, on damp ground, etc. ; they
produce no striking decompositions in the water which they
inhabit, and they soon perish in a putrefying liquid.

It is quite otherwise with the Schizomycetes, which, on
account of their want of chlorophyll, are reduced to live on
ready-organized substances, as are Fungi generally. The
Schizomycetes, therefore, produce in their substratum, or in
the fluid which they inhabit, very considerable and striking
decompositions. They perish in pure water, containing no
decomposable substance. They grow, therefore, exclusively
in organic liquids, or in water or on damp spots where there
is an abundance of organized matter.

Though we are thus certainly justified in separating the
Schizomycetes from the Phycochromaceae, i.e. from the
Algae, it still remains to be decided how they are to be
limited from the animal kingdom. In fact, the Schizomycetes
stand at that stage in the evolution of organic beings at
which it is not possible to draw a sharp line of demarcation
between the two kingdoms. Their kinship with the mouth-
less monads has often been remarked, and one is inclined
more and more to 'unite the latter with them. I restrict
myself to indicating this point, while provisionally I still
exclude these forms from the Schizomycetes ; they require
much further and exhaustive study. Unfortunately this is
true in a high degree of the Schizomycetes themselves ; both
the morphological and systematic as well as the physiological
relations of this group of Fungi are still very insufficiently
investigated. Doubts and uncertainties of many kinds have
still to be removed.

Among the forms which are included among the Schizo-
mycetes in the following pages, are many which have often

Schizomycetes. 3

hitherto been described as Algae, but which, on account of
their want of chlorophyll, and their decomposing power, must
be reckoned among the Fungi.

The Fungi here treated of are the smallest with which
we are acquainted. The form of the cells is various — round,
ovate, elliptic, cylindrical, etc. They live isolated, singly or
in larger or smaller swarms, or in many cases united in pairs,
or many together in threads or groups. Many forms are
always motionless ; others, on the contrary, show a more or
less active spontaneous movement, which is frequently
effected by flagella. In this case the cells swim about
swiftly, rotating round their longitudinal axis. In other
cases the movement is an oscillating one or the threads
alternately bend and straighten themselves, etc.

But even the motile forms for the most part possess
certain stages in which they are motionless. In this case,
usually, countless aggregated cells excrete a gelatinous or
slimy mass, which either presents a sharply bounded,
variously shaped contour — round, sac-like, ragged, or even
branching — or else is without definite outline. Such a
gelatinous colony is designated a zooglaa ; it is a resting-
stage, which often precedes the formation of spores, and
often also occurs in typically motionless forms.

The formation of spores is known in many Schizomycetes ;
it has been most accurately observed in Bacillus subtilis, in
which I will briefly describe it. The cells of the genus
Bacillus are short cylindrical rods, which increase by repeated
transverse division, and have a flagellum at each end, by the
active vibration of which the rod is moved. In spore-form-
ation the greater part of the contents collects at one point
of the rod, which often projects as a swelling, and is sharply
marked off from the other empty part of the cell. After-
wards this strongly refringent, dark-looking body (the spore)

4 Synopsis of the Bacteria and Yeast Fungi.

disarticulates itself from the barren part of the cell, which
then perishes, and the mature spore remains behind. These
spores possess the power of enduring adverse influences of
various kinds without injury to their vitality. They can
remain a long time in the ground, and then years after
proceed with their development ; they can also germinate
at once. At germination the spore first loses its brilliancy,
and swells up somewhat ; then the membrane of the spore
bursts in the middle. The inner part of the spore projects
through the opening, and grows to a new rod, the base of
which is sheathed by the split membrane, which is often not
thrown off for some time.

When we attempt to define the genera and species of
the Schizomycetes, as we are wont to do with other
plants, we encounter great difficulties, which must first be
shortly mentioned. The question is — What, in these Fungi,
is to be considered a genus and a species ?

That there exist a number of different genera, i.e.
groups of distinct forms, in the Schizomycetes, is almost
universally admitted. But there are two opposed views con-
cerning the limitation of these genera. Naegeli recognises
only a few very variable groups of forms, while Cohn
establishes a whole series of genera, which he sharply
distinguishes, and which he divides into numerous species.
To me it seems very probable that several really distinct
and constant genera exist, e.g. Micrococcus (in an extended
sense), Bacillus, Spirillum, and Sarcina; while others of Cohn's
genera are only stages of development. I should decidedly
allow that the number of species is far smaller than one
would judge from Cohn's classification. For many of these
species are very probably only forms which have been
differentiated by the influence of various external agencies,
and have become more or less constant

Schizomycetes. 5

It is in part quite impossible, especially in the genera
Micrococcus and Bacterium, to indicate morphological
distinctions between the species. We are in these cases
confined exclusively to physiological distinctions ; we employ
differences in chemical action for the limitation of species.
The Schizomycetes, as has been already stated, excite
peculiar decompositions in their substratum ; they transform
complicated chemical combinations into simpler ones. This
chemical action consists (i) in the production and excretion
of colouring matters ; (2) in the exciting of various fermen-
tations ; and (3) in the decomposition of the humours of
animal and human bodies, whereby diseases arise. We
distinguish, therefore, (i) chromogenous, (2) zymogenous, and
(3) pathogenous species respectively.

But especially in relation to those forms which belong
to the two last subdivisions does the greatest uncertainty
reign. Nay, in regard to the pathogenous Schizomycetes
such untrustworthy, even foolish, assertions and so-called
observations have been published, that only the greatest
foresight can guard against errors.*

There is left, therefore, especially for the systematist,
nothing but to accept Cohn's conscientious researches,
provisionally to adopt his classification and nomenclature as
the only one which is founded upon botanical principles, and
to add to it only what has been discovered by trustworthy
investigations. The nonsense which Hallier and Co. have
tried to introduce into the science naturally remains un-
regarded.

* This arises chiefly from the fact that many medical men, who have
tried to investigate these things, have been totally unskilled in the use
of the microscope, at any rate with high powers, and have often also
been untrained in the methods of observation. An eminent physician of
the United States, Dr. Schmidt, solemnly asserted that the Bacillus
tuberculosis of Koch was only a fat-crystal ! — TR.

6 Synopsis of the Bacteria and Yeast Fungi.

KEY TO THE GENERA.

1. Cells round or ovate ... ... ... ... ... 2

Cells cylindrical ... ... ... ... ... 5

Cells lanceolate, flat, spirally twisted ... ... Spiromonas

2. Cells isolated or united in chains or formless gelatinous

masses ... ... ... ... ... Micrococcus

Cells united in considerable numbers in colonies of definite outline 3

3. Colonies hollow, with a simple peripheral cell-layer... Cohniq
Colonies solid, with cells throughout their substance ... 4

4. Cells united in a small but definite number in regular

families ... ... ... ... ... Sarcina

Cells united in a large and indefinite number in irregular

colonies ... ... ... ... ... Ascococcus

[Cells in chains, each chain surrounded by a gelatinous

sheath ... ... ... ... ... Leuconostoc\

5. Cells shortly cylindrical, single, or loosely combined in twos

or a few together ... ... ... ... Bacterium

Cells long, cylindrical, united in threads ... ... ... 6

6. Threads isolated or felted together ... ... ... 7

Threads enclosed in roundish gelatinous masses ... Myconostoc

7. Threads unbranched ... ... ... ... ... 8

Threads with evident branching ... ... ... Cladothrix

8. Threads straight, or nearly so ... ... ... ... 9

Threads spirally wound or bent ... ... ... ... n

9. Threads conspicuously articulated, rather short ... Bacillus
Threads mostly not conspicuously articulated, long ... 10

10. Threads very slender ... ... ... ... Leptothrix

Threads thicker ... ... ... ... Beggiatoa

11. Threads short, with few spirals, or simply bent, rigid Spirillum
Threads longer, with numerous spirals, flexile ... Spirocfuzla

I. MICROCOCCUS, Cohn ("Beitrage zur Biologic,"
i. p. 151.)

Cells colourless or of a pale tint, round or oval-elliptic,
motionless, dividing in one direction only. The daughter-
cells either soon separate from one another, or remain united
in a chain of two or more, or form a zoogloea. Formation
of the spores not certainly knowa

Micrococcus. 7

What I have said above of the distinctions of the species is especially
true of this genus. The accepted species of Micrococcus show very
little or no difference in form and size, and there remains only chemical
action as a means of separating the species, which is therefore treated
somewhat fully.

A. — CHROMOGENOUS SPECIES.

i. M. prodigiosus, Cohn (I.e., p. 153).
Monas prodigiosa, Ehrenberg.
Palmella prodigiosa, Mont.; Cooke, "British Fresh-
water Algae," p. 12.
Zoogalactina imetropha, Sette.
Bacteridium prodigiosum, Schroter.

Cells round or oval, colour-
less, about "5-1 p,* in diameter;
forming at first rose-red, then
blood-red, at last pallid gela-
tinous masses. (Fig. i.)

On nitrogenous substances,
e.g. on boiled potatoes, meat,
wheat-bread, white of egg, starch- „. *

Fig. i.— Micrococcus prodigwsus,
paste, etC. Cohn, X 1200 (from nature).

M. prodigiosus is that organism which produces the long-known
peculiar appearance, formerly designated " blood-rain," on bread, on
the "host," etc. It forms at first little rose-red points and heaps,
which by degrees increase to rounded bright-red spots, and afterwards
become confluent into widespread, even dripping, blood-red patches.
These consist of a red-tinted mucous mass, in which thousands of
millions of Micrococcus cells are embedded. These cells are them-
selves colourless, but they secrete the red colouring matter in the
mucus. This colouring matter is very similar to fuchsin in its physical
and chemical relations. It is not soluble in water, but completely so
in alcohol ; the solution, evaporated and again dissolved, is orange-
red ; the colour is changed by acids into a bright carmine, by alkalies

* i n (pronounced mu) = -ooi mm. = 5^3 of an inch, nearly.

8 Synopsis of the Bacteria and Yeast Fungi.

into yellow. In the spectroscope it shows, among others, a character-
istic broad absorption band in the green.

Palmella mirifica, Rabenhorst, can scarcely be anything different.
(See Journal of the Royal Microscopical Society, 1882, p. 655.)

2. M. luteus, Cohn (I.e., p. 153).

Bacteridium luteum, Schroter.

Cells elliptic, somewhat larger than in M. prodigiosus,
with highly refractive cell-contents ; forming, on a solid sub-
stratum, clear yellow drops, which at first are as large as
a poppy-seed, and afterwards as a half-peppercorn ; at last
drying up to flat shield-shaped umbilicate discs. On nutrient
fluids this species forms a thick yellow skin, which becomes
plaited when luxuriantly developed

On boiled potatoes, etc.

Colouring matter insoluble in water, unchanged by sulphuric acid
and alkalies.

3. M. aurantiacus, Cohn (I.e., p. 154).

Bacteridium aurantiaeum, Schroter.
Cells oval, about i '5 /* long ; on a solid substratum in
orange-coloured drops and spots, which at last coalesce
into equal-sized patches. On nutrient solutions it forms a
golden-yellow skin.

On boiled potatoes and eggs.
Colouring matter soluble in water.

4. M. fulvus, Cohn (I.e., p. 181).

Cells round, about 1*5 p. in diameter; at first forming
rusty conical tolerably firm drops of £ mm.
in thickness, which increase and finally pro-
duce extended gelatinous masses. (Fig. 2.)
On horse-dung.

5. M. chlorinus, Cohn (I.e., p. 155).
Cells round (?), forming yellowish-green or

Micrococcus. 9

sap-green mucous masses, or in fluids sap-green layers,
which by degrees colour the whole fluid yellow-green.
On boiled eggs.

The colouring matter is soluble in water ; it is not reddened by
acids.

6. M. eyaneus, Cohn (I.e., p. 156).

Bacteridium cyaneum, Schroter.

Cells elliptic ; producing on slices of potato an intense
blue, which penetrates also into the interior, or even to the
opposite side of the slice. In fluids it forms a zoogloea,
which at first is colourless, then bluish-green, and at last
intense blue.

On boiled potatoes.

The colouring matter is soluble in water ; the solution is at first
verdigris-green, but afterwards usually becomes clear blue. It is
coloured intense carmine by acids, and then by alkalies blue or sap-green
respectively. In the spectroscope it shows no absorption bands, but
only a darkening of the less refractive half.

7. M. violaceus, Cohn (I.e., p. 157).

Bacteridium violaceum, Schroter.

Cells elliptic, larger than those of M. prodigiosus ;
occurring in bright violet-coloured gelatinous drops, which
unite to form larger spots, reaching 6 mm. in diameter.

On boiled potatoes.

B. — ZYMOGENOUS SPECIES.

8. M. urese, Cohn (I.e., p. 158).

Cells round or oval, 1*25-2 /* in diameter; isolated or
concatenate or forming a zooglcea on the surface of the
fluid. (Fig. 4&)

In urine.

M, urea is the ferment of ammonia fermentation. If fresh urine is
allowed to stand exposed at a sufficient temperature (30° C.), it loses its

IO Synopsis of the Bacteria and Yeast Fungi.

acid reaction after a few days, becomes neutral, and finally alkaline,
while the phenomena of fermentation are observed. The urea disappears
and is changed into carbonate of ammonia, while at the same time
alkaline urates and phosphate of ammonia and magnesia are eliminated.
This decomposition takes place only when the Micrococcus is developed
in the fluid.

9. M. Crepusculum (Ehrenberg), Cohn (I.e., p. 160).

Monas Crepusculum, Ehrenberg.

Cells round or shortly oval, very small,
scarcely 2 p. in diameter; isolated or forming
Fig. 3.— Micro- a zoogloea, (Fig. 3.)
cZfZm Tafter In and on various infusions and putrefying

Ehrenberg). fluids.

The common form of Micrococcus, which appears in all sorts of
decaying substances and in infusions, in company with Bacterium
Termo.

10. M. Candidas, Cohn (/.£, p. 160).

On boiled potato-slices, forming snow-white points and
spots.

[n. M. amylivorus, Burrill (American Naturalist, xvii.,
1883, p. 319).

Cells oval, single or united in pairs, rarely in fours, never
in elongated chains, embedded in an abundant mucilage
which is very soluble in water, i-i '4 p long, 7 p. broad ;
width of a pair 2 /*, of four united about 3 //. ; movements
oscillatory.

In the tissues of plants, causing the so-called " fire-blight "
of the pear tree, and similar phenomena in other plants.

Through the action of this organism, the stored starch is destroyed
by fermentation, and carbonic acid, butyric acid, and hydrogen are
given off. It may be cultivated in pure starch, in water maintained at
the temperature of ordinary summer weather.]

Micrococcus. 1 1

C. — PATHOGENOUS SPECIES.

12. M. vaccinse, Cohn (I.e., p. 161).

Microsphcera vaccines, Cohn.
Cells round, '5-
75 fj. in diameter;
isolated or united in
chains and heaps of °
two or more, also

forming a ZOOglcea. Fig.4.— a, Micrococcus vaccinat ; b, M. urea (after
/p- \ Cohn) ; c, M. ovatus (after Lebert).

In fresh lymph from cow or human pocks, as also in
the pustules of true small-pox.

According to many undoubted investigations, M. -vaccincE must be
regarded as the active element of vaccine lymph ; it is by its means that
the infectious principle is conveyed in cases of small-pox. By filtering
the lymph, the solid constituents can be separated from the fluid ; on
using the latter for inoculation, no effect is produced, while inoculation
by the former regularly excites the production of pocks. Moreover, that
the Micrococci, and not, as might be suggested, the lymph-cells, are the
effective constituents of the solid residuum, follows from the fact that
lymph which has been exposed to the air for some time grows gradually
less effective. For it begins to putrefy, and, as the process of decay
advances, the Micrococci disappear more and more, under the influence
of the putrefactive Bacteria.

13. M. diphtheriticus, Cohn (I.e., p. 162).

Cells oval, -3-1 p. long; single or concatenate, or forming
bundles and colonies of various shapes.

On the so-called diphtheritic membranes, which are found
especially on the mucous surfaces of the throat, the pharynx,
the air-passages, etc., but also appear on those of the sexual
and digestive organs, as well as on wounds, etc.

This Schizomycete is of extraordinarily great pathological importance.
For the disease spreads itself, from the centre of its first introduction,
through the lymphatic vessels and the tissue which surrounds them,

12 Synopsis of the Bacteria and Yeast Fungi.

into the connective tissue, the kidneys, and the muscular tissue; and
at last reaches even the blood-vessels, where it produces the greatest
destruction. The fungi stop up the capillaries and thereby rupture them.
Even the thinner bones and cartilage are destroyed by the diphtheritic
processes. The consequences of the introduction of these fungi are
therefore enormous.

14. M. septicus (Klebs), Cohn (I.e., p. 164).

Microsporon septicum, Klebs.

Cells roundish, '5 ft. in diameter ; united in chains or
heaps, or forming a zooglcea.

On wounds, especially in all the affections which are
named pyaemia and septicaemia.

In the various suppurations and putrefactions of the body, in
decomposition and poisoning of the blood, the Micrococci play an
important part. Whether all the manifold phenomena are caused by
M. septicus, or several species are not rather concerned in their pro-
duction, is questionable. In wounds, even in the secretion from the
fresh surfaces, we find Micrococci, which quickly multiply, produce
inflammation and fever, and penetrate deeper and deeper, destroying the
tissues in their course. If then they reach the blood-vessels, there arise
stoppages and suppurations ; the same phenomena are observed in the
lungs and the liver.

15. M. bombycis (Bechamp), Cohn (I.e., p. 165).

Microzyma bombycis, Bechamp.

0 Cells oval, '5 /JL in diameter ;

o single or in chains. (Fig. 5.)

In the gastric juice and in-
testines of silkworms, in which
§ they produce the so-called
o° "schlaffsucht" (in French "la
flacherie," one of the silkworm
diseases), a contagious affec-
from tion, of which the animals die
wonn in a short time.

Micrococcus. 1 3

[16. M. insectorum, Burrill (I.e., p. 319).

Cells obtusely oval, isolated or in pairs, rarely in chains,
•7—1 p, (usually '8 /x) long, '55 p, broad; movements oscil-
latory only ; forming a zooglcea (?).

In the digestive organs of the chinch-bug (Blissus
leucopterus).

These insects sometimes die off in great numbers during apparently
favourable weather in summer, with every appearance of a contagious
disease, and it is probable that this Micrococcus is the cause of the
disease. It may be cultivated in meat broth.]

[17. M. gallicidus, Burrill (I.e., p. 320).

Cells globular, single or in pairs, '5-72 p. in diameter;
movements oscillatory only.

In the blood of the domestic fowl affected with " chicken-
cholera ; " often described, but apparently never named
before.]

[18. M. suis, Burrill (I.e., p. 320).
Bacillus suis, Detmers.

Cells globular, or elongated and more or less contracted
in the middle, single or in pairs, rarely in chains, "j— '8 //. in
diameter.

In the blood and other fluids of pigs affected with
" swine-plague " or "hog-cholera."]

Besides the diseases mentioned, it is probable that many
others,, e.g. cholera, measles, scarlet fever, typhus, syphilis,
etc., are caused by Schi'zomycetous fungi. But no trust-
worthy observations are yet published concerning them. (See
Appendix C.)

[An enormous number of other Micrococci have been
described by Eberth, Chalvet, Hallier, etc., but for the
most part without names and without precision. (See also
Bacterium, Chapter IV., infra.}]

14 Synopsis of the Bacteria and Yeast Fungi.

D. — DOUBTFUL SPECIES.

19. M. griseus (Warming).

Bacterium griseum, Warming (" Om nogle ved
Danmarks Kyster levende Bakterier," p. 29 of
the Resume").

,o * Cells almost round or ovate, colourless, 2*5-4

© @@ V- l°nS (m tne act °f division, 6-7 p. long), i '8-
t «• 2-5 ^ thick. (Fig. 6.)
9 g In infusions of fresh and sea water.

* ft Since, according to Warming, this form occurs only in

Fig. 6. — Mi- a motionless state (and then forming no zoogloea), and

crococcus s;nce the cell-form answers better to that of the genus

eeo^after Micrococcus than to that of Bacterium, I have placed

Warming), it in the former.

20. M. ovatns (Lebert).

Panhistophyton ovatum, Lebert.
Nosema bombycis, NagelL

Cells oval, about twice as long as broad, rounded
at both ends, about 4-5, rarely 6 p, long, 2-3 (usually
2 *5 p. broad) ; isolated or united in pairs or little heaps.
(Fig. 4*)

In various organs of silkworms, their pupae, and imagos.

It is questionable whether the described cells belong to a Schizomycete.
They were first discovered by Cornalia at Milan, and named corpuscules
("corposcoli") ; according to him they are found also, although sparingly
and more by chance, in the blood of healthy silkworms. Afterwards,
these corpuscules (" corpuscules de Cornalia ") were recognised as the
cause of an epidemic disease of silkworms, called "gattine," or
" pefbrine."

Since the cells in their form and motionlessness agree very well with
Micrococcus, I have ranged them here.

Ascococcus. 15

[21. M. toxicatus, Burrill (I.e., p. 319).

Cells globular, single or in pairs, rarely in chains, -5 /t
in diameter ; movements oscillatory only.

In species of Rhus (Sumach), believed to be the
peculiar " poison " for which these plants are noted.

Transferred to the human skin, they multiply rapidly, penetrate
the epidermis through the sweat-glands (?), and set up the well-known
inflammation.]

II. ASCOCOCCUS, Cohn ("Beitrage," i. p. 154).

Cells colourless, very small, round, united in enormous
quantity into larger or smaller, globular or irregular families.
Families often folded, the folds again crimped, surrounded
by a firm, cartilagino-mucous capsule of a rounded form.

The value of Cohn's genus Ascococcus is, in my opinion, just as
questionable as that of the similarly named one of Billroth ; it is besides
doubtful whether or not they are identical. Possibly Ascococcus is only
a stage in the development of Micrococcus.

22. A. Billrothii, Cohn (I.e., p. 124).

Families lump-like, 20— 160 p, in diameter,
surrounded by a capsule as much as 15 p.
thick, covering the surface of the fluid in
a thick floccose layer. (Fig. 7.)

Forming a membrane on a solution of
acid tartrate of ammonia.

The colonies consist of a well-defined cartilagino-
mucous colourless envelope, in which either only
one or several families are enclosed. The families F'S- T.— Ascococcus
are of very varied size and form, solid, composed
of numerous extremely minute round cells. The
Fungus produces in its nutrient fluid a peculiar
decomposition ; it generates out of the ammonic tartrate contained
therein butyric acid and butyric ether, and changes the originally acid
fluid into an alkaline one, while free ammonia is evolved. The liquid
has then the characteristic smell of milk or cheese.

Billrothii (after
Cohn). 6, the in-
vesting capsule.

1 6 Synopsis of the Bacteria and Yeast Fungi.

III. LEUCONOSTOC,Van Tieghem (Ann. Set. Nat.,

1873)-

[Cells colourless, very minute, globose ; united in flexuose
and intertwined chains, which are enclosed in thick, lobed,
gelatinous sheaths. Sheaths aggregated into subglobose,
brain-like clusters, which present a pseudo-parenchymatous
internal structure. Spores isolated in the chains, globose,
terminal or intercalary.

This genus is distinguished from Ascococcus, in addition to the
spores, by the fact that the families are not solid, each chaplet of cells
being separated from its neighbours by a thick layer of gelatine. Its
analogy to Nostoc is remarkable, the main difference being the want of
chlorophyll In fact, it bears the same resemblance to that genus that
Cohnia does to Clathrocystis.]

[23. L. mesenterioides (Cienkowski), Van Tieghem.
Ascococcus mesenterioides, Cienkowski.

Families collected in
large masses, which may
measure i— i^- inch across
or more, polygonal by
mutual pressure. Cells in
long intertwined chains,
colourless, spherical, '8-1 '2
p. in diameter; each chain
surrounded by a thick
gelatinous sheath. Spores
spherical, with a thick
membrane, i '8-2 /t in dia-
meter. (Fig. 8.)

Fig. 8. — Leitconostoc mcsenterioides, X 520. _

a, section of a portion, showing the pseudo- <~>n DCet-rOOt SUgar,

parenchymatous structure, and the inter- and the sacks vessels,
calary and terminal spores ; i-n, a spore, .

and its development (after Van Tieghem). CtC., employed in the

Cohnia. 17

manufacture; can also be cultivated on macerations of
dates and carrots, and in the juice of the same, and of beet,
and has occurred spontaneously in the sap of turnips and
in molasses.

This, the " gomme de sucrerie " of the French, " froschlaich, "
or frog-spawn, of the German sugar manufacturers, causes a great loss
when it is allowed to take hold. It forms large whitish gelatinous
masses, which grow very rapidly ; the gelatine is elastic, almost car-
tilaginous, and insoluble in water. It renders acid the originally
neutral liquid in which it develops. When a spore germinates, the
middle layer of the cell-wall swells up, the spore proper elongates, and
divides into two, which separate, and repeat the process. When the
development has ceased, certain of the cocci increase in size, thicken
their cell-wall, and become changed into spores. — TR.]

IV. COHNIA, Winter: Clathrocystis (Henfrey), Cohn
(pro parte).

Cells roundish, in a simple peripheral layer surrounded
by a common gelatine, forming hollow, round or afterwards
irregular bladders or ^esicles, which finally are reticulately
pierced. Multiplication of the cells by repeated bipartition ;
of the families by the protuberance and separation of
daughter-families.

As I comprehend it, Cohn's genus, Clathrocystis, embraces both
Algse and Fungi. Since, then, the generic name was first used for an
Alga (Cl. (eruginosa, Henfrey), it is advisable to leave it for that
species, and to make the species which belongs to the Fungi the type
of a new genus, to which I have given the name of Cohnia, in honour
of Professor Dr. F. Cohn, of Breslau, who has gained so much dis-
tinction in the investigation of the Schizomycetes.

24. C. roseo-persicina (Kiitzing).

Protococcus roseo-persicinus, Kiitzing.
Pleurococcus r.-p., Rabenhorst ; Cooke, "British

Freshwater Algae," p. 6.
Microhaloa rosea, Kiitzing.
Bacterium rubescens, Lankester, p.p. ( Quart. Jour.

1 8 Synopsis of the Bacteria and Yeast Fungi.

Micr. Sri., xiii. 408, pi. 22-3 ; xv. 206 ; and xvi.

27, pl- 3)-

Clathrocystis roseo-persicina, Cohn.

\Monostroma rosea, Currey.]

\Beggiatoa roseo-persirina, Zopf (pro parte).~\
Cells round, oval, or, by mutual pressure, polygonal,
varying from rose to purple-red, reaching 2^ fj. in diameter.
They form at first small solid families, in which the single
cells are bound together by gelatine, while the whole family
is surrounded in addition by a gelatinous envelope. Later,
the families become larger, globular or ovoid, and finally
irregular bodies, which are hollow and filled with a watery
fluid, and reach a diameter of 660 p. (= f mm. or -^s inch).
In these the cells form a simple peripheral layer. These
vesicles are often torn or perforated ; in the end they pre-
sent an elegant network, which finally breaks up into
irregular rags and tatters. (Fig. 9.)

In marshes, floating on the surface or amongst Algae
and Lemna ; often also in a room, in water in which Algae,
etc, are decaying.

The single hitherto known species of this genus is distinguished by
its red colouring matter, which is essentially different from that of
Micrococcus prodigiosus, and is designated "bacterio-purpurin." It is
insoluble in water, alcohol, etc., is changed by hot alcohol into a brown
substance, and is moreover characterised by its optical behaviour. For
in the spectroscope it shows strong absorption in the yellow, less in the
green and blue, as well as a darkening in the more refrangible half of
the spectrum.* Each individual cell is surrounded by a dense, almost
cartilaginous membrane ; its contents are at first homogeneous, but as
it grows older one or more dark granules t can be observed in it, which
are nothing else but pure eliminated sulphur.

[By the kindness of Mr. J. Levick, then President of the Birmingham

* For the spectrum, see Quart. Jour. Micr. Set., xiii. 425. — TR.
t The granules are the "loculi" of Lankester, and the "spores"
of other authors.— TR.

Cohnia.

2O Synopsis of the Bacteria and Yeast Fungi.

Natural History Society, I have been favoured with specimens of a
supposed Alga from his famous garden pond (the home of so many
rarities), which I at once recognized to be this species. It occurred in
great quantity, floating freely in the water when young, but sinking
among the debris at the bottom when old and tattered ; its beautiful
peach colour renders it very striking among the green Algae with which
it is frequently entangled. It was accompanied by Monas Okanit,
Ehrenberg, which appears to be identical with Chromatium Weissii,
Perty ; but I could not find any other of the so-called forms of Bac-
terium rubescens, described by Lankester as occurring in company
with it.— TR.]

V. SARCINA, Goodsir (extended).

Cells roundish, dividing in two or three dimensions of space.
Daughter-cells connected for some time, forming small solid
families or plates, which are often again in their turn united
to form larger colonies. Families usually consisting of four
or a multiple of four cells.

25. S. ventriculi, Goodsir (Edin. Med. and Surg.

Journal, 1842, p. 430).
Merismopedia Goodsirii, Husem,
M. ventriculi, Robin.

Cells roundish, united in groups of four, eight, sixteen,
or a few more, flattened at the points of contact, forming
little cubes which are
rounded off at the corners.
Individual cells reaching
4 ft. in diameter; colonies
constricted at the parti-
tion walls of the cells,

about !3oo United in thdr tUm tO

(after Lurssen). form larger masses. Cell-

contents greenish, yellowish to reddish-brown, not con-
spicuously refringent. (Fig. 10.)

Sarcina. 2 1

In the stomach of healthy and diseased persons, and
the higher animals; also occurring in other parts of the
body, and according to Dr. Ferrier in the blood (Quart.
Jour. Micr. Sci., xiiL 163).

26. S. urinse, Welcker.

Merismopedia urintz, Rabenhorst.

Cells very small, i "2 p in diameter, united in families
of from 8 to 64 ; eight-celled families 2-3 //,, 64-celled 4^5 p
in diameter.

In the bladder.

27. S. litoralis (Oersted).

Erythroconis litoralis, Oersted.
Merismopedia litoralis, Rabenhorst
Cells round, or, before division, oval, 1-2 p., seldom 2
or more /«. in diameter, united into
families of four, six, or eight, etc.,
which in their turn form larger
colonies (as many as 64 groups of
four in a colony). Plasma colourless,
but in each cell from one to four red

. . . , ._,. Fig. ii.— Sarcina litoralis,

granules Of Sulphur. (Fig. 1 1. ) X 660 (after Warming).

In putrefying sea-water.

28. S. Reitenbacliii (Caspary).

Merismopedium Reitenbachii, Caspary.
Cells round, before division ovate-elliptical, about 1-5
-2 '5 /A in diameter, at the time of division prolonged to
4 p. ; seldom single or in twos and threes, for the most
part united in fours or eights, less often in sixteens or
more. Cell-walls colourless, lined with a rose-red layer of
plasma.

22 Synopsis of the Bacteria and Yeast Fungi.

On submerged parts of water-plants, on decaying pieces
of the same, and floating free in fresh water.

The families contain at most 32 cells ; those consisting of 8 round
cells measure 9'9 yu in length, 4-9 /t in breadth ; plates of 8 cells in
the act of separating are 6'6 ^ long, 4-9 /* broad ; the same of 1 6 cells
have a length of i6'6 /*, and a breadth of IO'7 ft..

Perhaps also Merismopedia violacea (Breb.), Kutzing, belongs to the
Fungi. It agrees closely with S. Reitenbachii in size, but is distin-
guished by its colour, and especially by the fact that the cells are not
unfrequently united in one family to as many as 128. Very similar but
hitherto, I believe, only found in Sweden, is Merismopedium chon-
droidaim, Wittrock.

29. S. hyalina (Kutzing).

Merismopedia hyalina, Kutzing. -*

Cells round, almost colour-
less, 2 -5 p in diameter ; families
usually composed of from 4 to
24 (seldom more) cells, reaching
15 /x, in diameter. (Fig. 12.)
In marshes.

,* 420 (after

Hepworth (M_

croscopical Journal, v., 1857, p. I, pi.
i. fig. 2), is coloured a lively green, and besides looks very little like a
Sarcina, and shall therefore only be mentioned.

Besides the foregoing species of Sarcina, Fungi belonging to this
genus have been observed on various substratra — on cooked potatoes
(in little chrome-yellow heaps), on cooked white of egg (in clear yellow
spots), also in fluids, even in the blood of healthy and unhealthy
persons, and in the mouth.

VI. BACTERIUM, Cohn ("Beitrage," i. p. 168).

Cells shortly cylindrical, elongated-elliptical or fusiform,
increasing by transverse division, spontaneously motile. The
daughter-cells either separate from one another soon after
division, or remain united in a chain of two or more. The
formation of a zoogloea is also frequent. Spore-formation
like that of Bacillus.

Bacterium. 23

A. — COLOURLESS SPECIES.

30. B. Termo, Dujardin ("Zoophyt," p. 212).
Monas Termo, Miiller.
? Palmella Infusionum, Ehrenberg.
Zooglxa Termo, Cohn.

Cells shortly cylindrical, oblong, about 1*5-2 p. long,
with a flagellum at each end. (Fig. 13.)

In the most various substances capable of putrefaction,
especially in great num-
bers in macerations of -' »
meat, etc. [A supply • * * i '
can be obtained in a , <k *
few hours by placing i f •
a bit of meat in water, vt C.
at a sufficient tempera- « *
ture.]

Bacterium Termo is the
ferment of decay ; it pro- p;g. ^.—Bacterium Termo; b, the zoogloea form
duces the decay of organic (a and b, after Cohn, x 650 , c, after Dai-
substances, and multiplies linger, x 4000).

abundantly so long as any putrescible material is present, while it
disappears when the decay is completed. It may be obtained with
certainty by putting a piece of meat into water, and leaving it to itself,
allowing the vessel to stand open in a warm place. In consequence of
their enormous power of multiplication, the Bacterium cells which are
conveyed by the air into the fluid, or which adhere to the meat, form
in a short time so numerous a progeny, that even in twenty-four hours
the water shows a decided milkiness, which is caused by the Fungus
cells floating in it. Moreover that B. Termo is the cause of the decay,
and does not, as might be supposed, appear secondarily in the decaying
substance, is easily shown by a simple experiment. For if the air is
allowed to penetrate without hindrance to a putrescible substance, the
decay begins very soon, because the air always contains a number of
Bacterium cells. But if the putrescible organic substance is strongly
heated (above 50° C.) and then protected from the air, it does not

24 Synopsis of tlie Bacteria and Yeast Fungi.

putrefy. It might indeed be objected that the air itself or the oxygen
thereof causes the decay ; but this objection also can be easily refuted.
Air may be admitted to easily putrefying substances which have been
strongly heated, but be deprived by filtration through cotton-wool of
solid bodies (and therefore of Bacterium cells) — and in spite of the
admission of air no decay will result.

31. B. Lineola (Miiller), Cohn (I.e., p. 170).

Vibrio Lineola, Miiller.

V. tremulans, Ehrenberg (sec. Cohn !).

Bacterium triloculare, Ehrenberg.

Cells exactly
similar to those of
B. Termo, but
larger, 3 to 5 ^
long, as much as
i '5 fi broad, with
two flagella at one
end.* (Fig. 14.)

In various in-
fusions, without
especial fermenta-
tion.

Fig. ^—Bacterium Lineola; b, the zoogloea form (a.
and b, after Cohn, X 650 ; c, after Dallinger, X 3000).

32

B. lito-

, Warming

(I.e., p. 29 of the Resume").

Cells ellipsoidal or elongated, gradually
rounded off at the ends ; length 2-6 /A, breadth
i '2-2 -4 p.; colourless, motile or stationary,
but never united in chains or zooglceae, nor
in large heaps. (Fig. 15.)

Only in sea-water.

* [The text says, " mit zwei Geiseln an einem
Ende ; " but see the figures. — TR.]

Bacterium. 25

33. B. fusiforme, Warming (I.e., p. 30, Resume).
Cells fusiform, with very acute ends, 2-5

/u. long, '5— '8 fi thick, in a spongy layer on the
surface of the water. (Fig. 16.)
In sea-water.

34. B. Navicula, Reinke et Berthold

(" Die Zersetzung der Kartoffel

durch Pilze," p. 21).
Cells fusiform or elliptic, nar-
rowed towards both ends, pretty
large, partly motile, partly station-
ary, with one or more dark spots
in the interior, which are coloured
blue by iodine. (Fig. 17.)

3 . Fig. 17.— Bacterium Navicula, X

In rotting potatoes. 94o (after Reinke and Berthold).

B. — CHROMOGENOUS SPECIES.

35. B. synxanthum (Ehrenberg), Schroter, in Cohn

(I.e., p. 120).

Vibrio synxanthus, Ehrenberg.
V. xanthogenus, Fuchs.

Morphologically not different from B. Termo ; "j—i i*-
long, moving actively, single or united in chains up to five
in number.

Causing the so-called "yellow milk."

Milk, which has been boiled, and some time afterwards coagulated,
often suddenly assumes a lemon-yellow colour, while the caseine by
degrees nearly disappears. The milk, originally neutral, becomes first
acid, and then intensely alkaline. The filtered lemon-yellow fluid
becomes amber-coloured on evaporation ; the resulting yellow-brown
crust is not soluble in alcohol or ether, but completely so in water.
Alkalies do not affect the colour, which is instantly changed by acids.

26 Synopsis of the Bacteria and Yeast Fungi.

36. B. syncyanum (Ehrenberg), Schroter (I.e., p. 124).

Vibrio syncyanus, Ehrenberg.
V. cyanogenus, Fuchs.

Morphologically the same as the preceding.
Producing the " blue milk."

The colouring matter is changed by potash or soda into a peach-
blossom red, while acids restore the original colour. Ammonia, on the
contrary, only slightly changes the blue to violet.

37. B. seruginosum, Schroter (I.e., p. 122).

In the so-called green or blue pus, which is at times
found in wounds, etc. Resembling B. Termo.

Even in this case the actively moving Fungus cells are
themselves colourless; they secrete the colouring matter,
which is verdigris-green, often passing into blue, in the
matter which surrounds them.

[38. B. violaceum (Bergonzini).

Chromobacterium violaceum, Bergonzini (Ann.
Soc. Nat. Moden., xiv., 1880; see Bot. Cen-
tralbl., i. 1528).

Rods isolated, motile, cylindrical, similar to those of
B. Termo, '6-1 p. thick, 2-3 fi long, of a violet colour.

On solution of white of egg. Pigment insoluble in
water, slowly soluble in ether, rapidly in alcohol. The
ether dissolves out a red-violet colouring matter, the alcohol
a deep blue one.]

VII. BACILLUS, Cohn (I.e., p. 173).

Cells elongated cylindrical, almost always combined in
straight rod-like (not at all or slightly constricted} rows or
threads, increasing by transverse division. They form a
zoogloea, but often also occur in dense swarms, without the
secretion of gelatine. Reproduction by spores.

Bacillus. 27

The genus Bacillus is very near to Bacterium ; Bac-
terium Lineola especially is very similar to single Bacillus
cells. But they can be distinguished by the fact that in
the longer Bacterium cells self-division has already begun,
while in equally long Bacillus cells no trace of division can
be perceived.

The species are partly always motionless, partly spontaneously
motile, passing however at times into a condition of rest. The rod-
like cell lengthens itself by intercalary growth to about double its
original length, and then breaks up by a transverse division into two
daughter-cells, which often separate from one another, often also
remain united. Since the products of repeated divisions are arranged
end to end, there arise filaments which are often bent in a zigzag
fashion, often also straight, apparently unjointed, but the joints may be
brought into view by the application of staining materials. The de-
velopment and germination of the spores in Bacillus has been already
described. The demarcation of the different species is difficult in this
case also.

A. — ZYMOGENOUS SPECIES.

39. B. subtilis (Ehrenberg), Cohn (I.e., p. 175).
Vibrio subtilis, Ehrenberg.

Cells cylindrical, about
twice as long as broad,
as much as 6 /A long, fur-
nished with a flagellum at
each end. Usually several
united together in pseudo- X" 0 o
filaments, which are like- Fig. i%.— Bacillus subtms, with spores

., ,, ., , (after Cohn).

wise motile, flexile, and

provided with a flagellum at each end. Spore-forming
rods three or four times as long as broad, isolated or united
in threads. Spores for the most part somewhat thicker
than the rods. (Figs. 18, 19, 200.)

28 Synopsis of the Bacteria and Yeast Fungi.

In various infusions and substances ; most probably also
in the rennet-stomach of living animals.

Fig. 19. — Bacillus subtilis, X 4000 (after Dallinger).

According to Cohn, it produces the butyric fermentation and is also
the efficient cause in the ripening of cheese.

An extraordinary and peculiar power of resistance is possessed by
the spores of B. subtilis and other species. They are not killed off
by boiling, but are thereby excited to speedier germination, which of
course brings into consideration the duration of the boiling. A quarter
of an hour's boiling does them absolutely no harm, while after an hour
most of them, and after two hours all of them are killed. Heating
them above 80° C. kills them sooner. They are not affected by poisons
and weak acids.

40. B. tremulus, Koch, in Cohn (I.e., ii. p. 417).

Very similar to
the preceding, but
more slender and
usually also shorter,
always with a flagel-
lum at each end.
Spores conspicuously
Fig. 20.-*, Baciii™ mttiiu; b, B. tremui™, with thicker than the cells,

spores ; c, B. antkracis, united in threads, form- often lateral. ( Fig.
ing spores, X 500 (all after photographs by Koch).

2O0).

On the surface of decaying plant infusions, forming a
thick gelatinous membrane.

Bacillus. 29

41. B. Amylobacter, Van Tieghem (Bull Soc. Bot.

France, xxiv.).
\Clostridium butyricum, Prazmowski.]

Morphologically like B. subtilis, but distinguished by
the fact that at certain times it contains starch in its cells,
which can be easily recognised by the blue colour produced
on the addition of iodine.

In the cells of laticiferous plants, in decaying plant
infusions, etc.

According to Van Tieghem's first communications, this species is
the cause of cellulose-fermentation. Afterwards B. Amylobacter (and
not B. subtilis] was indicated by him and Prazmowski (Bot. Zeitung,
1879, No. 26) as the ferment of butyric fermentation (Vibrion butyrique
of Pasteur). According to Prazmowski, B. Amylobacter is especially
and essentially distinguished from B. subtilis by the mode of germina-
tion of the spores. The germinating thread in the former species is
protruded, not at the equator, but at one of the poles of the sphere.
But it appears to me inadvisable to found a new species on this dis-
tinction, as Prazmowski desires.

[As little is known about B. Amylobacter in England, I append a
passage of Van Tieghem concerning it, translated from the Bulletin of
the Societe Botanique de France, 1880, p. 284: "Ordinarily, as we
know, when B. Amylobacter attacks starch-containing parenchyma, it
first dissociates the cells by dissolving their intermediate lamellae ; then
it causes the membranes of the cells thus separated to swell up, and
dissolves them by degrees, without attacking the granules of starch
which they enclose (as in potato, bean, etc.). In Adoxa Moschatellina
it is quite different. The Amylobacter still begins, it is true, by de-
stroying the intermediate lamellae, and separating the cells, the puncta-
tions of which " (he is speaking of the sub-epidermal layer of the
rhizome, macerating in water) " are then open to the outside. Pene-
trating into the cavity by one of these punctations, it proceeds to
develop itself there among the starch granules. At the same time it
attacks these granules, and causes them by degrees to disappear,
without exercising any action upon the cellulose membrane. When it
has completely dissolved and absorbed the grains of starch within the
cell, the Amylobacter forms a brilliant s_pore in each of its articulations,
and disappears. With its membrane unaltered, and the mass of spores
which fills it, the cell then fulfils the part of a sporangium." According

30 Synopsis of the Bacteria and Yeast Fungi.

to Van Tieghem, it is the action of this saprophyte which causes plant-
tissues, immersed in water, to decay. He has even recognised the
characteristic traces of its action in the remains of silicified fossil plants
of the Carboniferous period ; Ann. Set. Nat. Bot., ix., 1879, p. 381.
-TR.]

42. B. Ulna, Cohn (I.e., i. p. 177).

Threads broader than in
B. subtilis, slightly flexile, with
a dense fine-grained plasma.
Single cells as much as 10 p.
long, 2 p. broad. Spores ob-
long-cylindrical. (Figs. 21, 22.)
In various infusions, e.g. of

Fig. -.-Bacillus Ulna (after Cohn).

Appears to be scarcely different from B. subtilis. Intermediate
forms between the two have been observed.

Fig. 22. —Bacillus Ulna, X 3000 (after Dallinger).

B. — PATHOGENOUS SPECIES.

43. B. anthracis, Cohn (I.e., p. 177).

Exactly like B. subtilis, but motionless and without

23.— Development of Bacillus anthracis from a 'spore, and formation of spores
in the threads (after Ewart).

Bacillus.

flagella ; cells 4 p. or more long, very slender, for the most

part united into

long, often bent,

threads. Spores not

at all or little thicker

than the threads,

1-5-2-2 jtlong. (Figs. \$^*i.W "Of*

20r, 23, 24«.) ^%ATX?> I

In the blood of
animals which have

died of splenic fever ;

Fig. 24. — a, Bacillus anthracis, from the blood of a
cow that had died of splenic fever, examined after
death ; b, B. ruber, X 600 (after Cohn).

the cause of splenic fever in cattle, sheep, etc., and of
" pustula maligna," woolsorters' disease, in man.

B. anthracis and the pathological phenomena engendered thereby
are the most accurately known of all the diseases induced by Schizo-
mycetes. The Bacilli are found without exception in the blood of
animals which have died of splenic fever, and it is sought to infer that
they are the cause of the disease. So long as only the vegetative
threads were known, it was difficult to prove this ; for these are capable
of living only a relatively short time, and blood which contains them
alone soon loses its power of infection. The remarkable thing about
splenic fever, however, is that it often breaks out in a neighbourhood
quite suddenly, then disappears for a long time, to appear again just
as unexpectedly without any transference from without having taken
place. From these facts it must be concluded that the contagium can
preserve its infectiveness for a considerable time. The discovery of the
spores of B. anthracis, which nevertheless are formed only in the blood
of dead animals, or when the blood of animals affected with splenic
fever is slowly dried, explains this long-lasting power. For, moreover,
the spores of B. anthracis possess great capabilities of resistance to
external influences, especially to dryness, so that they are capable of
further development even after years. These spores are buried in the
ground with the bodies of diseased animals which have died, and when
there means of dispersion are open to them. If then they get in any
way into the bodies or the blood of cattle, etc., they germinate, the
rods which proceed from them multiply in abundance and soon com-
mence their destructive work.

[This species is now known to move at one stage of its existence,

32 Synopsis of the Bacteria and Yeast Fungi.

and also to form a zoogloea (Qitart. Jour. Micr. Sci., xviii. 163). Klein
describes, I.e., xxiii. 260, a torula-like variety which sometimes passed
on the same thread into the typical Bacillus. — TR.]

[44. B. tuberculosis, Koch.

Rods slender, about one-half to one-third of a human

^f** red blood-corpuscle

'j in length, i.e. 3-4 p.
V^ long, and in breadth

<*> \ J*^. one-sixth of their

B fa length. Spores not

\ L/ "^ thicker than the

' * * " threads> at>out -5 p

iniameten (Fig-

Fig. 25.- Bacillus tuberculosis, from human sputum, * G Walls °f

prepared by Heneage Gibbes's method ; a X 1200 ; tuberculous Cavities,

in the sputum, and

even in the breath of phthisical patients, in degenerated
scrofulous glands, in fungous joints, and in the bones of
tuberculous animals (Koch), and in all kinds of tuberculous
new formations (neoplasms).

This was first discovered by Koch, by staining with methylene
blue in alcohol, followed by a solution of vesuvin ; the methods of
Ehrlich, Baumgarten, and Heneage Gibbes are given in the Appendix,
p. 103.]

[45. B. leprse, Hansen (Virchow, Archiv, 1880, p. 32).

Rods slender, resembling those of B. tuberculosis, but
about *7 //. broad. Spores not thicker than the threads.
(Fig. 26.)

In the "lepra" formations of the skin, in the liver,
the spleen, the testicles, the lymph-glands, the mucous
membrane of the mouth, throat, etc., of leprous patients,

Bacillus.

53

but, as it appears, not in the kidneys or the blood. The
" brown elements " always found in old tubercles are pro-

Fig. 26.— Bacillus lepree. a, cells from tubercles, fresh ; I, a
" brown element " coloured with methyl-violet, from a
tubercle treated with osmic acid ; c, bacilli, with spores
(a and b, after Hansen ; c, after Neisser).

bably agglomerations of spores and spore-forming Bacilli.
This species is acted upon by staining agents in the same
way as B. tuberculosis^

C. — CHROMOGENOUS SPECIES.

46. B. ruber, Frank et Cohn (I.e., i. p. 181).

Rods 6-8 p. thick, scarcely i /x thick, actively motile,
isolated or united from two to four together. Dividing rods
sometimes shorter, only 3—4 p. long. Secreting a brick-red
pigment, which is different from that of M. prodigiosus.
(Fig. 24.)

On boiled rice.

47. B. erythrosporus, Cohn (I.e., iii. p. 128).
Motile, short, slender rods, partly forming longer threads,

34 Synopsis of the Bacteria and Yeast Fungi.

in which numerous oval-oblong, bright shining, dirty red-
coloured spores arise. (Fig.

27.)

On a solution of extract
of meat, putrefying infusions

Fig. n.-Bac'm^erythrosporus (after of white of Cgg, and putrefying

Miflet). macerations of meat

This species forms partly little floating scales, partly continuous
membranes ; the threads finally dissolve to a jelly, thereby freeing the
spores, which then sink to the bottom, united in little gelatinous heaps.
The species is easily recognisable by the dirty-red colour of the spores.

VIII. LEPTOTHRIX, Kutzing ("Phycologia Gene-
ralis," p. 198), pro parte.

Threads very long and slender, unbranched, apparently
inarticulate, colourless, without motion, not granular, free or
felted together.

The Fungi assigned to the genus Leptothrix are of very
questionable value as species ; I therefore include the fol-
lowing with all reserve. Leptothrix-like formations are very
common in Bacillus.

Since this genus will probably remain only a short time among
the Fungi, I do not think it desirable to give it a new name now.
The greater part of the species of Leptothrix are typical phycochro-
maceous Algae !

48. L. buccalis, Robin (" Hist. Nat. V£g. Paras.," p.
345)-

Threads very long and slender, 7-1 p. (seldom some-
what more) thick, inarticulate, colourless, densely felted in
white masses. (See also Fig. 270.)

Mixed with Micrococci (usually also with Vibrio, etc.) in

Leptothrix.

35

the white slime of the teeth, on the epithelium of the mouth,
and in hollow teeth ; probably
the cause of dental caries.

The seat of this Fungus is espe-
cially in the canals of the dentine,
yet it also attacks the substance of
the enamel, which it destroys by
degrees. In those canals the Fungus
produces decided enlargements, and
afterwards their walls become pierced
by crevices and fissures, and break
to pieces. [According to recent
authors, the enamel must first be
attacked by the acids of the mouth,
before the Fungus can effect a lodg-
ment.]

49. L. parasitica, Kiitz-
ing (Bot. Zeit., 1847,
p. 220).

Threads very slender, for
the most part curled and
crisped, indistinctly jointed,
loosely felted, almost colour-

Fig. 2ja.— Leptothrix buccalis (after
Zopf). This is the form called
Zooglcea ramigera.

less, about i p. thick, 100-140 p long. (Fig. 28.)

Fig. 28.— Leptothrix parasitica, X 600 (after Kutzing).

Parasitic on Scytonemaceae and other allied Algae.

Perhaps also Leptothrix pusilla, Rabenhorst, and L. Lanugo, Kiitzing,
should be placed among the Fungi.

36 Synopsis of the Bacteria and Yeast Fungi.

IX. BEGGIATOA, Trevisan (" Prospetto della Flora
Euganea," p. 76).

Threads very long, but thicker than in Leptothrix, for
the most part indistinctly jointed, rigid, but actively oscillating,
embedded in gelatine, colourless ; protoplasm provided with
numerous, strongly refringent granules, which consist of
sulphur.

The genus Beggiatoa is easily to be recognised by the
strongly motile threads, which form usually chalk-white
or slimy masses, and in which the articulations cannot, as
a rule, be perceived without further treatment. In order
to see them, allow the threads to dry on the slide, and then
add sulphide of carbon, which by degrees dissolves the
sulphur granules which in the living Fungus obscure the
joints. The Beggiatose live for the most part in sulphur
hot-springs, where they decompose the compounds of
sulphur dissolved in the water, and eliminate free sul-
phuretted hydrogen. So that such water, enclosed in a
flask with Beggiatoa, evolves an intense smell of sulphuretted
hydrogen.

The accepted species of Beggiatoa are of very doubtful value ; they
are discriminated almost entirely by the thickness of the threads.

50. B. alba (Vaucher), Trevisan (" Nomencl.," p. 58).
Beggiatoa punctata, Trevisan.
Oscillaria alba, Vaucher.
Hygrocrocis Vandelli, Meneghini.

Threads without distinct articulations, forming dirty
or chalk-white gelatinous masses, 3-3 -5 p. thick. (Fig.
290.)

In sulphur springs and marshes.

Beggiatoa.

37

Var. marina, Cohn (B. CErstedtii, Rabenhorst).
Threads densely filled with blackish granules, only 2 ft
thick.

Fig. 29. — a, Beggiatoa alia, X 600 ; b, B. nivea, with the
plasma contracted, X 900 ; c, B. leptomitiformis, X 800 ;
d, B. tigrina, X 800 (a, c, and d, after Kutzing ; *, after
Rabenhorst). The engraver has made these threads too
thick, especially c.

Forming a delicate snow-
white gelatinous membrane on
decaying animals and Algae in an
aquarium with sea-water. (Fig.
30.)

Fig. 30. — Beggiatoa alba, var. ma-
rina, X 660 (after Warming).

51. B. nivea, Rabenhorst (" Flor. Eur. Alg.," ii. p. 94).
Leptonema niveum, Rabenhorst

Threads very slender, indistinctly jointed, i-i '5 fi thick
(according to Rabenhorst), forming undulated woolly tufts
of a chalk-white colour. (Fig. 29^.)

38 Synopsis of tJie Bacteria and Yeast Fungi.

In sulphur springs.

In Wartmann and Schenk's " Schweiz. Kryptog.," No. 639, this
species is published under the name of Symphyothrix nivea, Briigger.
Both the names given above are cited as synonyms, but only pro parte.
From the label attached I extract the following observations : — " Threads
inarticulate and motionless, only ^ro to 7555"' thick (= -5-1 '3 jt), parallel
and much entangled, in penicillate tufts, strings, and sheaves of very
unequal size, which are surrounded by a common, homogeneous, colour-
less gelatine."

52. B. leptomitiformis (Meneghini), Trevisan ("Flor.

Eug.," p. 56).

Oscillaria leptomitiformis, Meneghini.
Threads very slender, indistinctly jointed, about i '8-2 -5 /i
thick, forming a thin chalk-white slimy layer. (Fig. 29^.)
In sulphur springs.

53. B. arachnoidea (Agardh), Rabenhorst ("Flor.

Eur. Alg.," ii. p. 94).
Oscillaria arachnoidea^ Agardh.
O. versatilis, Kiitzing.

Threads pretty thick, distinctly jointed, strongly motile,
with rounded slightly curved
ends. Articulations as long or
half as long as broad. Threads
5-6-5 /* thick, forming thin,

Fig. ^.—Beggiatoa arachnoidea, x arachnoid, chalk-white gelatinous

320 (after warming). membranes. (Fig. 31.)

In sulphur springs and marshes.

54. B. pellucida, Cohn (Hedwigia, 1865, p. 82).

Threads about 5 p. thick, motile, distinctly jointed, with
rounded ends ; articulati9ns almost as long as broad, trans-
lucent, containing but few granules. (Fig. 32.)

In an aquarium with sea-water.

Beggiatoa.

39

Fig. 32.— Beggiatoa pellucida, x 400 (after Cohn).

55. B. mirabilis, Cohn (U, p. 81).

Threads very thick, motile, bent and curled in various
ways, with rounded
ends, distinctly
jointed, as much as
1 6 n thick ; articu-
lations about half
as long as broad,
filled with nume-
rous, pretty large
granules. Threads
twisted round and
entangled with one
another, forming a
snow-white web of
gelatinous threads.
(Fig. 33-)

With the preceding.

Fig. ^.—Beggiatoa mirabilis, X about 320 (after
Cohn).

DOUBTFUL SPECIES.

56. B. tigrina, Rabenhorst (" Flor. Eur. Alg.," ii.

P- 95)-

Oscillaria tigrina, Romer.

Threads pretty thick, oscillating, distinctly jointed, with
blunt and slightly bent, sometimes abruptly attenuated
and crooked ends, translucent, 3 -5-4 -5 p. thick; forming thin
white layers. (Fig. 29^.)

In marshes and on wood under water.

4O Synopsis of the Bacteria and Yeast Fungi.

57. B. minima, Warming (I.e., Resume", p. 15).

Very minute, actively motile and flexile. The longest
specimens about 40 p. long, i '8-2
p. thick; articulations discernible
in the form of delicate transverse
bars. Each joint about half as
long as broad. Without granules.
(Fig- 34-)

Fig. 34. — Beggiatoa minima, X
660 (after Warming).

In sea-water.

X. CLADOTHRIX, Cohn (" Beitrage," i. p. 204).

Threads like those of Leptothrix, very slender, colour-
less, not articulated, straight or slightly undulated, or even
in places twisted in irregular spirals, with false branching.

I can discover no sufficient distinction between Clado-
thrix and1 Streptothrix. Both are very doubtful genera.

Fig. 3S-— a, Cladothrix dichotoma, X 100 ; b, a part of the same, showing
the false dichotomy, X 600 (after Cohn).

Myconostoc. 41

58. C. dichotoma, Cohn ("Beitrage," i. p. 185).

Threads repeatedly and regularly dichotomously
branched, straight or slightly bent, about '3 /x, thick, form-
ing small tufts of £ or more mm. in diameter. (Fig. 35.)

In putrid water, partly floating on the surface, partly
attached to Algae.

The branching is here, just as with C. JForsteri, only apparent.
A thread splits itself down the middle into two halves, which lengthen
independently, and thus grow side by side, whereby the piece which
was separated is pressed on one side, and so appears as a branch.

59. C.F6rsteri(Cohn.)

StreptothrixFor-

steri, Cohn

(" Beitrage,"

i. p. 1 86).

Threads straight or
bent, in places twisted in
irregular spirals, sparingly
and irregularly branched,
separating into pieces of
various lengths. (Fig. 36.)
In the lachrymal canals
of the human eye, form-
ing tallowy or crumbling
masses, which are yel-
lowish-white or blackish,

I f~3'" long, and about i'" FiS- ?f>.—Cladothrix FSrsteri, X 600. a,
, . , \ i • i the threads embedded amongst Micro-

(i.e. about 2 mm.) thick. cocci (after Cohn).

XI. MYCONOSTOC, Cohn (" Beitrage," i. p. 183).
Threads very slender, colourless, inarticulate, but on
desiccation breaking up into short cylindrical fragments,

42 Synopsis of the Bacteria and Yeast Fungi.

variously bent and intertwined, surrounded by gelatine,
which forms spheroidal masses of 10—17 /x (or more) in
diameter. Multiplication by constriction and bipartition
of these gelatinous masses.

60. M. gregarium, Cohn (I.e.}.

Gelatinous masses floating on the surface of putrid
water, singly or heaped into little slimy drops ; exterior
boundary sharply denned. (Fig. 37.)

On water in which Algae were decaying.

Fig. 37.— Myconostoc gregarium. a, gelatinous spheroids,
containing the threads ; b, a spheroid in the act of
division ; c, the threads separated ; d, the threads break-
ing up into ring-shaped pieces (after Cohn).

[This species was recorded by Professor Lankester as a phase of
Spirillum Undula (Quart. Jour. Micr. Set., xiii. 424), but as no genetic
connection between the two has yet been traced, Cohn thinks it better,
at present, to keep it distinct. It derives its name from its resemblance
to Nostoc among the Algae. (Fig. 38.)— TR.]

Fig. 38.— Myconostoc gregarium, X 1500 (after Lankester,
who considers it a zoogloea form of Spirillum Undula).

Spirochceta. 43

XII. SPIROCH^TA, Ehrenberg (Abhandl. Berlin.
Akad., 1833, p. 313).

Cells united in long slender threads, which present a
considerable number of close spiral turns. The threads are
very actively motile ; in fact they swim forwards or back-
wards, rotating round their longitudinal axes, and can more-
over bend themselves in the most varied manner. Not
forming a zoogloea, but often felted in dense tufts.

Distinguished from Spirillum by the long, closely wound, flexile
threads.

6 1. S. plicatilis, Ehrenberg (I.e., p. 313).

Spirillum plicatile, Dujardin.

Spirulina plicatilis, Cohn.

Threads very short and slender, with numerous close
spirals, articulated, blunt at
the ends, 110-225 !"• l°ng
(according to Rabenhorst) ;
diameter of the single joints .^ rsQrs
(and thickness of the threads)
2-25 /A, according to Ehren-
berg. [Spores, according to Fig ^_spirMa plicatilis (a> ^

Van Tieghem, 8 p. in dia- a photograph by Koch; 6, after

meter.] (Fig. 39,)

In bog-water, among Algae.

This species is said by Koch to be distinguished from the others
especially by the doubly undulated contour of its filaments. But still
filaments with a simple spiral are very abundant. [Dr. Klein (Quart.
Jour. Micr. Sci., xv. 382) asserts that he has seen all intermediate
forms between this and Spirillum tenue, with which he unites it. — TR.]

62. S. Obermeieri, Cohn ("Beitrage," i. p. 196).
Morphologically almost the same as S. plicatilis, perhaps

44 Synopsis of the Bacteria and Yeast Fungi.

only distinguished by the fact that the threads are pointed

at both ends. (Fig. 40.)

In the blood of persons
suffering from febris recur rens,
and probably the cause of the
disease.

The threads of S. Obermeieri 'are
either extended in a straight line,
and wound in regular spirals, or
else they bend themselves, moving
with extreme rapidity in the most
varied fashion, so that the spirals
appear of unequal size, especially
at the most strongly bent places.
This species is found in the blood
of those suffering from intermittent
fever, and in fact only during the
recurring fever periods, or for a
short time thereafter. In the in-
tervals of freedom from fever they
disappear.

[It is a question whether this be not the same as the preceding
species, merely transpknted into a different habitat. — TR.]

Fig. tp.—Spirochatta Obermeieri (c,
after a photograph by Koch ; d, after
Weigert). In d the blood corpuscles
are represented ; the bent threads
show the form assumed shortly before
the cessation of the fever.

63. S. Cohnii, Winter ("Pilze," i. p. 61, 1884).
\_Spiroch(Kte denticola, Arndt.]
[S. dentium, Miller.]

Very similar to both the foregoing species, but always
shorter, and for the most part more
slender, than S. Obermeieri, and besides,
like that, pointed at both ends. (Fig. 41.)
In the slime of the teeth ; discovered
by Cohn ; figured by Koch (" Beitrage
zur Biologic," vol. ii. pt. 3, pi. xiv. fig. 8).
[Miller has shown that this is articulated,
like S. plicatilis.]

•^ _~
/ V

Fig. 41. — Spirochata.
Cohnii (after Koch).

Spiromonas. 45

64. S. gigantea, Warming (I.e., Resume", p. 21).

Threads cylindrical, blunt at both ends, about 3 //. thick,
with numerous spiral turns, the height of which is 25 ^,
the diameter 7-9 /*. Flexile. The articulations are not

lueta gigantea ; a, X 166 ; i, X 660 (after Warming).

visible, but at times the threads break up into joints.
Colour greyish. (Fig. 42.)
In sea-water.

The longest specimens showed sixteen turns ; flagella have not
been discovered.

.XIII. SPIROMONAS, Perty ("Zur Kenntniss der

kleinsten Lebensformen," p. 171).

Threads "flattened like a leaf, twisted round an imaginary
longitudinal axis." Multiplication by transverse division.

65. S. volubilis, Perty (I.e.*).

" Colourless, translucent [rounded at both ends], smooth,
without any obvious differentiation, motion
pretty swift, combined with a quick revolu-
tion round the axis about which the leaf-
like body is twisted. Body often twisted
very little, never forming more than a cir-
cumference. Length T^-^'"= i5-i8/*."
(Fig. 43-)

Fig. 43.— Spiromo-
nas volubilis, X
about 450 (after
Perty).

46 Synopsis of the Bacteria and Yeast Fungi.

In stagnant bog- water and putrefying infusions.

[This is often considered as an Infusorian. See Saville Kent's
"Manual of the Infusoria," p. 298. — TR.]

66. S. Cohnii, Warming (I.e., Resume", p. 20).

Cells flattened, but sometimes slightly angular, acutely
pointed at both ends, each with one
flagellum, with ij (seldom more) turn.
Spiral elongated, 6-9 times as high as
its diameter, 9-20 /x in height, i '2-3-5
p. in diameter. Breadth of the cells
i '2— 4 p.. Colourless, often with one
or two longitudinal striations. (Fig.

44-)
Fig. 44.— spiromonas jn stinking, very much decomposed

Cohnii, X 660 (after
Warming). Water.

XIV. SPIRILLUM, Ehrenberg (Abhandl. Berlin.

Akad., 1830, p. 38).

( Vibrio, Cohn ; Ophidomonas, Ehrenberg.) .
Cells cylindrical or slightly compressed, simply arcuate
or spirally twisted, rigid, with a flagellum at each end (?
whether in all species). Multiplication by transverse
division, the daughter-cells for the most part soon separat-
ing. At times also a zooglcea is formed. Spore-formation
similar to that of Bacillus.

I unite with the genus Spirillum, the Vibrio of Cohn, and the
Ophidomonas of Ehrenberg. The genus Vibrio, in fact, cannot be
sharply defined, since flagella have also been found in it. Cohn him-
self has already united Ophidomonas with Spirillum. Warming also
combines all three genera. Although the name Vibrio has priority,
still I have preferred the designation Spirillum, because gross misuse
has been made of the former, especially by non-botanists, so that it is
better to let it lapse altogether.

Luaa luiBH

50 that it

Spirillum. 47

67. S. Rugula (Miiller).

Vibrio Rugula, Miiller (" Infus.," p. 44).
Melanella flexuosa, Bory.

Cells 6-1 6 /A long, about
•5-2-5 /* thick, either only
simply arcuate, or with one
shallow spiral, bearing a
flagellum at each end, actively
rotating round its longitu-
dinal axis; the cells are
often felted in dense swarms.
Height of the spiral generally
6-10 p., diameter -5-2 p. Fig. 45._a> spirillum Rugula -, i, s.

always at the end Of Undula. (a, after Cohn ; b, afte

Koch's photographs).

the cell, globose. (Fig. 45^.)

In bog-water, and various infusions ; also in the slime
of the teeth, etc.

According to Warming, individuals occur the spiral of which reaches
a height of 13-20 p. and a diameter of 2-5-5 p. Plasma granular.

68. S. serpens (Miiller).

Vibrio serpens, Miiller (" Infus.," p. 44).

Cells half as broad as in the foregoing species, 11-28
p. long (according to Rabenhorst), 'S-i'i p. thick, with
several, usually three or four, spirals ; often united in long
chains; with a flagellum at each end. Also frequently
forming swarms. Height of the spirals 8-12 p., diameter
1-2-3 /*• (Fig- 46 a, b.}

In various infusions.

The dimensions recorded by Rabenhorst (23-28 /u long) presumably
refer to threads composed of several cells. According to Warming, the
spirals is sometimes as much as 22 p..

48 Synopsis of tJu Bacteria and Yeast Fungi.

Fig. 46.— a, Spirillum serpens ; b, the same, felted in a "swarm;"
c, S. tenue; d, S. Undula: e, S. volutans, X 650 (after Cohn).

69. S. tenue, Ehrenberg (" Die Infusionsthierchen.,"
p. 84).

Cells very slender, 4-15 /«. long, about 2-25 p. thick
(according to Ehrenberg), with at least

I J J 1 i£, usually, however, 2, 3, 4, or 5 spirals.

I | ) ) I Height and diameter of the spirals about
1.5—4 fj., or the diameter amounts to half
the height Moving very swiftly, but also
often almost motionless and felted in
dense swarms or masses, or united in a
zoogloea. (Figs. 46^, 47.)
In various infusions.

Fig. 47. — Spirillum

tenue, x 660 (after According to Warming, only I ft. thick, and the
Warming). spirals at times 8-10 /* high, with the diameter f - T'5

of the height. There appears to be some confusion between S. tenue

*nd 5. Undula.

STATE -NORMAL SCHWtt,

Lo»AnCele.,Cal.

Spirillum. 49

70. S. Undula (Mailer), Ehrenberg (AbhandL Berlin.

Akad., 1830, p. 38).
Vibrio Undula, Muller.
V. prolifer, Ehrenberg.

Cells 8-12 p. long, 1-1-1-4 P thick (according to Raben-
horst); spirals wider than in the foregoing, 4-5 p. high;
each cell for the most part embracing only ^ or i, seldom

Fig. 48.— Spirillum Undula, X 3000 (after Dallinger).

i \ to 2 or 3 spirals; a flagellum at each end. Very
actively motile, at times also forming a zooglcea. (Figs.
45^, 46^, 48.)

In bog-water and various infusions.

Ehrenberg gives for S. tenue a thickness of -^
of a line, for S. Undula only ^ of a line ; at the
same time, he says in the description, " Sp. fibris
valde tortuosis brevibus, validioribus."

According to Warming, 5". Undula is more variable
than was formerly admitted. The spirals are often
elongated, so that the cell appears almost straight ;
accordingly the height of the spirals varies from 3 to
io-5 fi, the diameter amounts to ={, or -f0 of the height,
the thickness of the cells "6-1-3 M-

Var. liter ale, Warming (I.e.,
sume, p. 23).

Re-

Fig. *,<).— Spirillum
Undula, var. //-
torale, X 66o(after
Warming).

5O Synopsis of the Bacteria and Yeast Fungi.

As much as 3 /x, thick, spirals elongated, each 5-10 /x
high, diameter ^ or ^ of the height (Fig. 49.)
On the shores of the Baltic Sea.

[71. S. amyliferum, Van Teighem (Bull. Soc. Bot.
France, 1879, p. 66).

Motile. Spiral of 2—4 turns, diameter of spiral 3—4 ft,
height 6-9 fji. Thickness of thread i'2-i'5 /*. At each
end a delicate flagellum. When growth has ceased, the
contents become amylaceous, so as to be coloured blue by
iodine, except at one place in each cell, where a spore is
afterwards formed. Spores oval, strongly refringent, 2 -5-3 p.
long, i -5 p. broad.

Each turn of the spiral is usually occupied by one cell, and forms
one spore. When the spiral has grown to four turns, two lateral septa
are formed, and the four cells separate into two equal portions, by the
solution of the intermediate layer of the median partition. While in
active growth the cell-contents are coloured yellow by iodine. The
spores are always placed at the end of a cell. In germinating, they
throw out a tube, which soon becomes curved, and then spiral. When
it has taken two turns, a central partition is formed. The similarity of
this to the formation and germination of a Bacillus spore is noticeable ;
S. amyliferum is most probably only a phase of B. Amylobacter, in
company with which it was found.]

72. S, volutans, Ehrenberg (Abhandl., 1830, p. 38).
Vibrio Spirillum, Miiller.
Melanella Spirillum, Bory.

Cells slightly attenuated towards the ends, gently
rounded, 25-30 p, long, about i'5~2 p. thick ; each cell with
2^-3^ (seldom more) spirals, the spiral 9-13 p, high, 6*5 p. in
diameter ; a flagellum at each end. (Fig. 46*.)

In various infusions, as well as in bog-water among Algae.

According to Warming, the spirals are often elongated, so that the
cell appears almost straight ; the diameter then amounts to only 1-5-4 M-

Spirillum. 5 1

Var. robustum, Warming (I.e., Resume, p. 23).

Thickness 2-4-5 /*» height of the spirals 10-20 p.,
diameter 1-3 /x. Usually with i^ turn. Sometimes with
two flagella at one end. (Fig. 50.)

In sea- water.

Fig. 50. — Spirillum •volu-
tans, var. robustum, X
660 (after Warming).

Fig. 51. — Spirillum sanguine*
X 600 (after Koch).

73. S. sanguineum (Ehrenberg), Cohn (" Beitrage,"

i. p. 171).
Ophidomonas sanguined, Ehrenberg.

Cells cylindrical, only seldom attenuated at the ends,
3 fi or more thick, of various lengths, with usually 2 (seldom
^ or 2^) spirals. Height of the spirals 9-12 /i, diameter
about § of the height ; a flagellum at each end. Cell-
contents coloured by numerous reddish bodies, with many
sulphur granules. (Fig. 51.)

In putrefying brackish wrater [and pond water?].

According to Warming, the longest specimens reach 65 ji. ; the
height of the spirals I5~37 M> while the diameter amounts to 3 or §, or
in small specimens \ - T'? of the height.

[According to Saville Kent, the Ophidomonas sanguined of Ehrenberg
is a true monad, and not identical with Cohn's Spirillum sanguineum.
(See " Manual of the Infusoria," p. 244, and infra, p. 94.) — TR.]

52 Synopsis of the Bacteria and Yeast Fungi.

74. S, violaceum, Warming (I.e., Resume", p. 5).

.,:/ Cells either crescent-shaped (and so

without a complete turn) or with i or i^
sPiral> broadly rounded at the ends, with
a flagellum at each. Cell-contents violet,
with a few sulphur granules. Height of the
spiral 8-10 /*, diameter 1-1*5 /*> thickness
of the cells 3-4 /*. (Fig. 52.)

violaceum, X 660 T , . . ,

(after Warming). *B brackish water.

75. S. Rosenbergii, Warming (I.e., Resume, p. n).

Cells with i or i^ turn, 4-12 /x long,
1*5-2-6 p. thick, colourless, but with ex-
tremely numerous strongly refringent sul-
phur granules. Spirals 6-7*5 /"• high, of
very varied diameter, which amounts at
the most to half of the height. Moving
actively and in the most varied fashion,

Fig. *,•?,.— Spirillum

Rosenbergii, x 660 but, as it seems, without flagella. (Fig.

(after Warming). \

In brackish water.

76. S. atteimatum, Warming (I.e., Resume", p. 25).
Cells strongly attenuated at the ends, usually with 3

spirals. The middle
spiral is large and close
(height about n /z, dia-
meter 6 /A), the end spirals
Fig. ^-spirillum attenuatum, x 660 are elongated (10 /z high,

(after Warming). 2 ^ jn diameter^ Thick.

ness of the cells 2 or i *2 /A. (Fig. 54.)
In sea-water.

Sphczrotilns. 53

77. S, Jenense (Ehrenberg).

Ophidomonas Jenensis, Ehrenberg (" Infusions-

thierchen," p. 44)

Ceils obtuse at both

ends, with flagella,

olive-brown, 40 p. long,

about 3^ u. thick, with

, . V -r- s F'g- *>$.— Spirillum Jenense, X 600 (after

£-2^ Spirals. (Fig. 55.) Ehrenberg).

Whether this is really a distinct species is hard to say, so long
as it is not found again in the original locality. Possibly it is identical
with S. volutans.

[Saville Kent classes this as a true monad (see "Manual of the
Infusoria," p. 244). Warming thinks it may be identical with O.
sanguined. — TR.]

APPENDIX.

With the Schizomycetes we may range several other
genera which are partly united with them by others without
remark, but which present so great peculiarities that it will
be better provisionally to separate them.

XV. SPH^ROTILUS, Kiitzing.

Cells roundish-angular or oblong, rounded at the corners,
united in great numbers in a colourless gelatinous sheath
to form long threads, which are densely tufted and en-
tangled in floating flakes. Multiplication by means of
vegetative cells, which isolate themselves and then form
new threads by continued subdivision. Reproduction by
spores, which are produced endogenously within the vege-
tative cells.

78. S. natans, Kiitzing (Linn&a, 1833, p. 385).
Flakes in the vegetative stage yellow-brown in the

54 Synopsis of the Bacteria and Yeast Fungi.

older parts, colourless in the younger, many times branched,
very slimy. During spore-formation, partly- milk-white,
partly red-coloured. Cells 4—9 /* long, 3 ju, thick. (Fig. 56.)
In stagnant and flowing water.

The flakes consist of an enormous mass of long, variously combined
threads, which are formed of rows of cells, surrounded by a slimy,

Fig. ^.-Spharotilus natans (after Kutzing).

evanescent sheath. These threads often assume a shrubby branched
form, and are attached to water-plants, or float in a thin layer on the
water. In the formation of spores, the protoplasm of the cells breaks
up into numerous minute, strongly refringent portions, which become
round spores, red at maturity, afterwards of a brown colour. These
are set free by the dissolution of the mother-cell. They germinate very
quickly, and grow into threads which are either isolated, or united with
the parent-threads or with • other threads as well. These daughter-
threads, proceeding from the germinating spore, are at first undivided ;
not till after a time do they break up into the typical rows of cells.
Sometimes the growth of the spores into threads takes place while they
are still within the mother-cell.

Spharotilus ochraceus, de Brebiss in litt., Kutzing, " Species Alga-
rum," p. 147, does not belong to this genus.

XVI. CRENOTHRIX, Cohn.

Threads cylindrical, somewhat clavately thickened up-
wards, articulated, provided with a sheath. Multiplication
by means of the joints, which escape from the sheath and
grow into threads. Reproduction by spores, which are
formed in the sheath by further subdivision of the joint-cells.
The spores either grow directly into threads, or form by
continued subdivision gelatinous colonies of roundish cells,
which afterwards produce threads.

Crenothrix.

55

79. C. Kiilmiana (Rabenhorst), Zopf ("Untersuch.
iiber Cren." (1879), p. 3).

Leptothrix Kuhniana, Rabenhorst.

Hypheothrix Kuhniana, Rabenhorst.

Crenothrix polyspora, Cohn.

? Palmellina flocculosa, Radlkofer.
Threads in whitish or brownish tufts, 1*5-5 p* thick,

Fig- 57- — Crenothrix Kiihniana (after Zopf). a, vegetative
threads ; b, Palmella form ; c, spore-forming threads.

increasing to 6-9 /A towards the end ; joints of very varied
lengths. Spores 1-6 //, in diameter. (Fig. 57.)
In wells and drain-pipes, etc.

56 Synopsis of the Bacteria and Yeast Fungi.

A Fungus which is often very troublesome, because it defiles the
water and stops up the narrower pipes. The cylindrical threads, some-
what clavate above, are visibly articulated ; the joints afterwards
separate from one another, but are then surrounded by a sheath, which,
originally colourless, becomes of a yellow or yellowish-brown colour by
impregnation with iron. The sheath, at first closed, is burst at last
by the continually dividing joints, which then escape. Each joint can
develop a new thread. In other cases, however, the thread remains
enclosed in the sheath ; its joints are divided by closely contiguous
transverse partitions into flat discs, which then break up by vertical
partitions into smaller roundish cells : the latter may be designated the
spores of the Fungus. They often develop, even while still within the
sheath, into new threads, which grow through the gelatinous swollen
sheath ; or else they leave the sheath, and undergo further develop-
ment outside it. They either grow into threads, or form by repeated
bipartition larger or smaller colonies of roundish cells, held together
by their membranes, which assume a gelatinous consistence. These
colonies are designated the Palmella form (probably the Palmellina
flocculosa of Radlkofer) ; each of their cells can again form a thread.

[According to Eyferth, Bot. Zeitung, xxxviii. 673, C. Kuhniana
is identical with Sph&rotilus natans. A. Giard, Revue Internal, des
Sciences, x. 190, in describing the infection of the drinking water of
Lille, in 1882, by this Fungus, says that the " microgonidia," which
are formed by transverse division of the clavate ends of the tubes,
exhibit for some time an active movement, and with a high power
(Hartnack, No. 12, immersion) he saw the flagellum. A full account
of this Fungus will be found in Quart. Jour. Micr. Set., 1873, P- l&3- —

( 57 )

CHAPTER II.

SACCHAROMYCETES.

The Saccharomycetes, or Yeast Fungi, are unicellular plants,
which multiply themselves by budding, and reproduce them-
selves by endogenous spores. They live singly or united in
bud-colonies, chiefly in saccharine solutions, where they excite
alcoholic fermentation.

In most of the Saccharomycetes the cells are round,
oval, or elliptic ; seldom are they elongated into cylindrical
tubes, which are divided by transverse partitions, and may
be regarded as the first indication of the formation of
hyphse, i.e. of a mycelium. For the purpose of multiplica-
tion the cell forms an outgrowth, which is filled with a
portion of the contents of the mother-cell, gradually assumes
the form and size of the latter, and separates itself from it
by a wall. Both cells can in like manner produce fresh
daughter-cells, which often remain for a considerable time
united with one another, and on separation continue to
grow independently.

The formation of spores succeeds most easily on a
moist solid substratum. Typically the whole cell-contents
divide themselves into 2—4 roundish portions, or contract
into a single spherical body. The portions of the contents

58 Synopsis of the Bacteria and Yeast Fungi.

surround themselves each with a membrane, and so pro-
duce the spores, which can bud like the vegetative cells.

To the Yeast Fungi (in the narrower sense) belongs the
capacity of decomposing the sugar of a fluid into alcohol
and carbonic acid, i.e. of exciting alcoholic fermentation.

The carbonic acid comes off in rapid streams of bubbles,
while the alcohol, as well as certain subordinate constituents
of sugar, remains behind.

The fermentation proceeds most energetically with re-
stricted access of air ; but, if the air is excluded for a long
time, the yeast cells perish.

The same is true of the Saccharomycetes, especially in
a botanical aspect, as of the Schizomycetes. Just as in
the latter case, so also in this, it is necessary to impose
a limit upon the accepted species, and only those founded
by trustworthy investigators can be considered. Of course
there remain even then many doubtful points • for the ma-
jority of the now accepted species of Saccharomycetes may
be only various forms of one and the same species, which
have become differentiated by changed conditions of growth.

XVII. SACCHAROMYCES, Meyen (in Wiegmann's
Archiv, iv. vol. ii. p. 100).

Unicellular Fungi, with vegetative increase by budding,
and reproduction by spores, which, for the most part, arise
by subdivision of the contents of the mother-cell.

A. — SPECIES NOT PRODUCING A MYCELIUM.

80. S. cerevisiae, Meyen (I.e.}.
Torula cerevisice, Turpin.
Cryptococcus fermentum, Kiitzing.
Cryptococcus cerevisia, Kiitzing.

Sacckaromyces.

59

Hormiscium cerevisitz, Bail.
[Saccharomyces minor, Engel ?]

Cells mostly round or oval, 8-9 //. long, isolated or
united in small colonies. Spore-forming cells isolated,

Fig. 58. — Saccharomyces cerevisite ; a, a bud-colony;
b, two spore-forming cells (after Lurssen).

11-14 /"• long; spores mostly three or four together in each
mother-cell, 4-5 p. in diameter. (Fig. 58.)

Vf

P4

Fig. 59.— "Low yeast," Sacckaromyces cerevisiez l at the
same, budding actively (after Pasteur).

In beer, in both high and low fermentation.

The true beer-ferment is found in the various sorts of

©

Fig. 60.—*' High yeast," Saccharomyces cerevisia ,'
same, budding actively (after Pasteur).

beer, in both modes of fermentation ; it is cultivated on a

60 Synopsis of the Bacteria and Yeast Fungi.

large scale, and then yields the German yeast, a mass which
consists of yeast-cells and water.

[There are two races of this species, "high" yeast and "low"
yeast. The cells of "low" yeast (Fig. 59) are slightly smaller and
more oval in shape than those of "high" yeast (Fig. 60), and in
budding produce less ramifications, so that there is an absence of the
globular clusters which are so striking a feature in the development of
"high" yeast, when examined at an early stage of growth. " Low"
yeast never rises to the surface of the fermenting fluid, which is thus
left clear, but it produces, in the opinion of Englishmen at least, an
inferior beer. This is known in England as " Bavarian" beer. With
high yeast, the newly formed cells rise to the surface as the fermenta-
tion proceeds, and there form large foam-like masses. It is doubtful
whether the names "high" and "low" arose from these different
positions of the yeast, or from the difference in the temperatures at
which they work. High yeast ferments at a temperature between 16°
C. and 20° C., while low yeast is usually employed at a temperature
of from 6° C. to 8° C., and rarely more than ip° C. In Pasteur's
(from a morphological point of view) confused ' ' Etudes sur la Biere, "
these are considered as distinct species, but this position is untenable.
S. minor, Engel, found in fermenting bread, is probably only a form
of the same.— TR.]

81. S, ellipsoideus, Reess ("Bot. Untersuch. iiber
Alkoholg.," p. 82).

Cells elliptic, mostly 6 /* long, isolated or united in little
branched colonies. Spore-
f°rmmg ceNs mostly iso-

J. ff " ft ^

'^£ tf Vl lated ' sP°res 2~4 together

,-£? £P= // K3X3 ^n eacn mother-cell> 3~3 '5 /*

Cx in diameter. (Fig. 61.)

X -C^^? X f?/70

Fig. 6l.-., ^^^c«^^«,; *. Producing spontaneous
the same, more highly magnified. fermentation in must ; [this
is the ordinary ferment of wine].

82. S. conglomeratus, Reess (I.e., p. 82).

Cells almost round, 5-6 /x, in diameters united in clusters,

Saccharomyces. 6 1

which consist of the numerous cells produced by budding

from one or a few mother-cells. Spore-forming cells often

united in twos, or with

a vegetative cell ; spores <^-->

2-4 in each mother-cell.

(Fig. 62*.)

In wine at the begin-

ning of the fermentation, Fig 62_a> Saccharomyces exigMts . b> s. con.
and on decaying grapes. giomeratus, x 600.

83. S. exiguus, Reess (I.e., p. 83).

Cells conical or top-shaped, about 5 p. long, reaching
2-5 //, in thickness, united in sparingly branched colonies.
Spore-forming cells isolated, each with 2-3 spores, which
lie in a row. (Fig. 62^.)

In the after-fermentation of beer.

84. S. Pastorianus, Reess (I.e., p. 83).

Cells roundish-oval or elongated-clavate, of varied size.

Fig. 63. — Saccharomyces Pastorianus; a, the same, more highly
magnified (after Pasteur).

Colonies branched, consisting of primary clavate cells, 18-

62 Synopsis of the Bacteria and Yeast Fungi.

2?. p, long, which produce secondary roundish or oval
daughter-cells, 5-6 p. long. Spore-forming cells roundish
or oval ; spores from 2 to 4 together, 2 /A in diameter.
(Fig. 63.)

In the after-fermentation of wine, and fruit-wine, or
spontaneously fermenting beer. [The "caseous ferment"
of Pasteur ; may be obtained sometimes in English yeast.]

85. S, apiculatus, Reess (I.e., p. 84).

Carpozyma apiculatum, EngeL

Cells lemon-shaped, shortly apiculate at each end, 6-8
p. long, 2-3 p. broad, sometimes slightly elongated, and,

according to Hansen,
towards the end of their
growth becoming oval;
daughter-cells arising only

from the ends of the
mother-cell ; for the most

Fig. 6^-Saccharon.yces adulate, Part soon isolated, rarely
x about 500. united in small, scarcely

branched colonies. Spores unknown. (Fig. 64.)

In the principal fermentation of wine, and in other
spontaneous fermentations. [On all kinds of fruit, stone-
fruits, etc., in must, and in certain kinds of beer.]

86. S. sphaericus, Saccardo (" Fungi Italici," fig. 76).
Cells of various forms; the basal ones (of a colony)

oblong or cylindrical, 10-15 p. long, 5 p. thick; the
others round, 5-6 p. in diameter, united in bent, branched,
often clustered families. Spore-formation unknown.
(Fig. 65.)

On the fermenting juice of Lycopersicum esculentutn,
the tomato.

Saccharomyces. 63

[Saccardo, who regards this as a Hyphomycete of low organization,
says (" Michelia," i. p. 90), " Occurring in minute, flatly convex, gre-
garious and confluent, dirty-white heaps ; conidia perfectly spherical,
5-6 /j. in diameter, collected in variously curved, branched and often

Fig. 65. — Saccharomyces sphtericus (after Saccardo).

clustered chains, separating with difficulty, hyaline, usually supported on
oblong or subcylindrical bases, 10-15 p X 5 M-" There is a strong like-
ness between this and Hormiscium album, Bonorden, except in habitat. ]

87. S. glutinis (Fresenius), Cohn ("Beitrage," i. p.

187).
Cryptococcus glutinis, Fresenius.

Cells round, oval, oblong, elliptic to shortly cylindrical,
5-11 fj. long, about 4 fi broad, isolated or ^

united in twos, seldom more together. Cell-
membrane and contents colourless, when
fresh ; but, when moistened again after dry-
ing, with a faintly reddish central nucleus.
Spore-formation unknown. (Fig. 66.)

On starch-paste, slices of potato, etc., F
forming rose-coloured, slimy spots, which (after Cohn).
have at first a diameter of ^-i millimetre, but by degrees

64 Synopsis of the Bacteria and Yeast Fungi.

spread and become confluent in patches of as much as one
centimetre broad.

The colouring matter is unchanged by acids and alkalies.

B. — SPECIES PRODUCING A MYCELIUM.

88. S. Mycodenna, Reess (I.e., p. 83).

Mycoderma cerevisia, and M. vini, Desmazieres.
Hormiscium vim, and H. cerwisice, Bonorden.
Cells oval, elliptic or cylindrical, about 6-7 /* long,
2-3 p, thick, united in richly
branched colonies. The cells
are often elongated, so as to
resemble a mycelium. Spore-
forming cells as much as 20 p.

Fig. 67.— Saccharomyces Mycoderma, long; Spores 1-4 in each mOther-
buddmg; a is the Hormiscium vini 11 /TTjo-c fi , fiQ \
of Bonorden ; 6, a more cylindrical CCU> lr«* ° 7> °°- ^

form. On fermented fluids, sauer-

kraut, juices of fruit, etc, forming on beer and wine the
so-called "mould."

This and the following species reach in their development

Fig. 68. — Sacckarowyces Mycodenna, from home-made " ginger-beer,"
with spores, X 500.

the highest rank among the Saccharomycetes. The cells
often form, especially in watery fluids, long tubes, which
are divided by transverse partitions, and fall into single
pieces at those points. These bud, in their turn, in the
same manner.

Saccharomyces.

While the true Yeast Fungi grow submerged in the higher layers of
the fluid, and there excite active alcoholic fermentation, the " mould"
grows on the surface, without exciting fermentation. When artificially
forced to grow submerged, of course a little alcohol is produced, but the
Fungus soon perishes.

Although the growth of the layer
of " mould " goes hand-in-hand with
the souring of the wine or beer, yet
the Saccharomyces is not the cause of
the latter. The formation of vinegar
from alcohol is produced rather by
other Fungi, whose systematic position
is still undetermined. According to
some, it is a species of Vibrio (Spiril-
lum) which causes this decomposi-
tion.

89. S. albicans (Robin),

Reess.
Oidium albicans, Robin.

Cells partly round, partly
oval, oblong or cylindrical, 3-5-
5 p. thick ; the round ones 4
/A in diameter, the cylindrical
ones 10 to 20 times as long as
thick. Bud-colonies mostly con-
sisting of rows of cylindrical
cells, from the ends of which
spring rows of oval or round
cells. Spores formed singly in
roundish cells. (Fig. 69.)

On the mucous membrane
of the mouth, especially of in-
fants, forming the disease known as aphtha, or thrush.
Also in animals.

This Fungus appears in the form of larger or smaller greyish-white
heaps, which nevertheless do not consist exclusively of the Saccharo-

F

66 Synopsis of the Bacteria and Yeast Fungi.

myces, but also contain Schizomycetes and the mycelia of moulds.
When cultivated, the Fungus forms long-jointed, richly branched threads;
at the upper end of each articulation there is usually a crown or bundle
of shorter cells, which are oval or round in form, and bud in their turn.
In other cases, all the cells of a bud-colony remain short, and assume
a rounded form. This Fungus excites alcoholic fermentation only in a
small degree.

According to Grawitz (Virchow's Archiv fur Path. Anat. und
Phys., vol. Ixx. p. 557), S. albicans is identical with S. Mycoderma.

C. — DOUBTFUL SPECIES.

90. S. guttulatus (Robin).

Cryptococcus guttulatus, Robin (" Hist. Nat. Veg.

Paras.," p. 327).

Cells elliptic or elongated-ovate, 15-24 p. long, 5-8 p. thick,
brown, opaque, with two to four colourless drops, isolated or
from two to five together. Spore-formation unknown.

In the oesophagus and intestines of mammals, birds,
and reptiles.

[91. S. coprogenus, Saccardo et Speggazini (" Fungi

Italici," fig. 911).

Effused, superficial, rather compact, dirty-rose colour;
conidia ovoid and then globose, 12-14 p. long, 10-11 /*

Fig. 70. — Saccharomyces coprogenits, X 500 (after Saccardo).

broad, forming very short chains or solitary, often provided
with a tail-like appendage (? from germination), clouded

Saccharomyces. 67

within, when in clusters pale rose-coloured, hyaline
(" Michelia," ii. p. 287). (Fig. 70.)

On fermenting human ordure, where it forms a some-
what waxy layer, almost like a Corticium. This also is
considered by Saccardo to be a Hyphomycete.]

[92. S. olei, Van Tieghem (Bull. Soc. Bot. France,
vol. xxviiL).

Cells oval, arranged in branching threads, 4 p long, 2 '5
ft broad ; cell-contents pale rose-colour.

In olive oil. The oil is changed in appearance by the
growth of this Fungus, becoming white and milky from
saponification. No gas is disengaged during growth, nor
is any special odour perceptible. The ordinary Saccharo-
mycetes will not grow in oil.]

[Dr. Klein, Quart. Jour. Micr. Sci., 1883, p. 268, describes a pink
" Torula," consisting of cells 9—10 /x in diameter, which he assumes to
be those of S. cerevisitz. It formed pink droplets on a nutrient fluid ;
the colour was only developed on the free surface, and not in the
submerged growth.

What is called the "ginger-
beer " plant, used in country dis-
tricts to produce home - made
ginger-beer, consists of "low" or
sedimentary yeast, and S. Mycoder-
ma, together with various species
of Bacillus, probably B. Ulna and
B. sub tilts, and in addition the
" Mucor-ferment " of Pasteur FiS- T1- — Mucor-ferment of Pasteur
(Fig. 71), which is considered by W™°r racemose), from ginger-beer,
him to be a submerged vegetating form of Mucor racemosus.— TR.]

CHAPTER III.

CLASSIFICATION.

THE classification of the Schizomycetes is at present in a
remarkable transition state. That presented in the fore-
going pages, Chapter I., is due in the main to Cohn, and
has been supported by Koch, Van Tieghem, and others.
It is founded upon the idea, which would obviously occur
first to an observer, that all the various morphologically
or physiologically distinct forms belong to different species.
This idea received strong apparent support from Koch's
experiments (Jour. Roy. Micr. Soc., 1881, pp. 950-952,
and Quart. Jour. Micr. Set., 1881, pp. 651-654) in the
cultivation of bacterial forms upon gelatine of sufficient
consistence to keep the progeny of any one germ in its
immediate neighbourhood, and thus prevent that mixture
of diverse forms which has been so often perplexing.
Under these conditions, according to Koch, Micrococcus
produced nothing but Micrococcus, Bacterium nothing
but Bacterium.

In opposition to this theory, Na'geli, Billroth, Hallier,
Hoffmann, Liiders, Cienkowski, Neelsen, Zopf, Haberkom,
and others maintain that in most cases a Schizomycete
passes through a series of adaptive forms — that a Micro-

Classification of the Schizomycetes. 69

coccus may become a Bacterium, a Bacterium a Bacillus, a
Leptothrix, or even a Spirillum and a Spirochaeta. Ray
Lankester (Quart. Jour. Micr. Sri., xiii., 1873, P- 4°^)
and Lister were the first to promulgate this opinion in
England; but the truth of the former's observations, on
Bacterium rubescens, has been partially denied by several
observers, and is not yet entirely free from doubt.

The first classification of the Schizomycetes was that
due to Ehrenberg, in 1838 (" Die Infusionsthierchen,"
P- 7S)» °f which the following is the essential part : —

• u. fig"1 - ••• •" •'• Bacterium

Cells straight { snake.like> flexiie ......... Vibrio

< flexile ... Spirochate

Cells spiral jrigid ......

It may be noted that Vibrio is here conceived to be
naturally straight-lined, but capable of bending in undula-
tions of a serpentine form, being thus distinguished from
Spirillum by the fact that the undulations lie all in one plane.
But most modern observers are agreed that the species
referred to Vibrio belong to two classes — the one, in which
the undulations are serpentine, being merely Bacillus ; the
other, in which they are spiral, being undistinguishable from
Spirillum. This is, therefore, another reason, added to those
which Dr. Winter has given (supra, p. 46), why the name
Vibrio should be dropped.

Cohn's first classification (1872) is merely a modification
of Ehrenberg' s.

A. Cells at times united in gelatinous families.

a. Cells round, Sphserobacteria ... ... Micrococcus

b. Cells oblong, Microbacteria ... ... ... Bacterium

B. Cells never united in gelatinous families.

a. Cells thread-like, Desmobacteria.

1. Threads straight ... ... ... Bacillus

2. Threads undulated -... Vibrio

70 Synopsis of the Bacteria and Yeast Fungi.

b. Cells spiral, Spirobacteria.

1. Spirals flexile ... ... ... ... Spirochate

2. Spirals rigid ... ... ... ... Spirillum

The division into sections A and B is founded upon a
mistake, since some of the forms in the latter are now
known to occur in a zooglosa. The Vibrio here mentioned
is distinct from Ehrenberg's Vibrio, and included only V.
Rugula and V. serpens.

This classification Cohn revised in 1875 (see Quart.
Jour. Micr. Sri., 1876, pp. 259-278), adding the genera
Sarcina, Ascococcus, Leptothrix, Beggiatoa, Crenothrix,
Streptococcus, Myconostoc, Cladothrix, and Streptothrix,
and moreover placing these and the old genera in company
with the analogous genera of Algae in one series, as Schizo-
phytae. But these changes attracted but little notice except
among specialists, and the arrangement given above, with a
few additions, is that familiar to the majority of the students
of Bacteria.

The growth of views inconsistent with this classification
will be seen by the following resume of a few of the con-
trary opinions. The earlier observers, whose opinions were
based on insufficient grounds, may be disregarded.

J. Lister (Quart. Jour. Micr. Sa\, 1873, pp. 380-408,
pi. 19-21) gave an account of several experiments with
Bacteria, in which great precaution was taken to ensure
accuracy, and in one case, of a Bacterium which appeared
spontaneously in milk, he observed coccus, bacterioid,
bacillar, and leptothrix forms, and recognised their genetic
connection.

Ray Lankester's investigation of Bacterium rubescens
(1873) nas Deen already noticed. Few even of succeeding
writers have gone further in uniting different and apparently
distinct forms. See also his further observations in the
same journal (1876, pp. 278-283), and infra, p. 85.

Classification of the Schizomycetes. 71

Geddes and Ewart (Proc. Roy. Soc., xxvii., 1878, p. 481)
confirm Lankester's results in the main. J. C. Ewart
(Quart. Jour. Micr. Sci., 1878, p. 161), after investigating
Bacillus anthrdcis, advocates the doctrine that Micrococcus,
Bacterium, and Bacillus are only phases of the same life-
history, "which," he says, "is doubtless common to all
Bacteria."

Cienkowski ("Zur Morphologic der Bacterien," 1878)
held (i) that the zooglcea form is analogous to the Palmella
form of chlorophyllose Algae ; (2) that Crenothrix, Lepto-
thrix, and Cladothrix give rise to the zoogloea forms of
Bacteria, e.g. of B. Termo and B. Lineola ; (3) that Bacteria
are transformed into Micrococci by subdivision, and into
Leptothrix by continued growth ; (4) that Micrococcus,
Bacterium, and the so-called Torula forms are not genetically
distinct.

W. Zopf (" Ueber den genetischen Zusammenhang von
Spaltpilz-formen," 1881) not only confirmed the views
which Cienkowski had previously expressed of the genetic
connection of Micrococcus, Bacillus, and Leptothrix, but
also asserted that Vibrio, Spirillum, Spirochseta, and
Ophidomonas can enter into the same life-cycle with these.
He investigated chiefly Cladothrix, Beggiatoa, and Creno-
thrix. But he allows that not all the Spaltpilze have this
pleomorphism, so that it is quite possible that some of them
occur under one form only.

C. von Nageli (" Untersuch. iiber niedere Pilze" (1882),
i. pp. 129-139) maintained that all known forms of Schizo-
mycetes are connected by intermediate links, and that any
division into species, however convenient for the purposes
of description, has no scientific value. He considers that
the same species can occur in widely different forms, ac-
cording to the circumstances of its nutrition.

72 Synopsis of the Bacteria and Yeast Fungi.

J. Haberkorn (Botan. Centralblatt, x., 1882, p. 100)
puts forward the opinion that all Cohn's four tribes are
forms of a single large genus with numerous species, which
show alternations of generations and pleomorphy.

W. Zopf ("Zur Morphologic der Spaltpflanzen," 1882)
adduced further evidence to prove the truth of the view
that all the genera of the Schizomycetes described by Cohn
and others, are simply stages of development dependent
upon nutrition.

W. Miller (Archiv fur exp. Pathol. und Pharmak.,
xvi., 1882, p. 296) states that he observed transitional forms
between Leptothrix buccalis and other genera, viz. coccus,
bacillus, and spiral forms; and again (Berichte Deutsch.
Bot. Gesell., i., 1883, pp. 221-224) he traced the growth of a
Leptothrix from the teeth of a dog into forms more or less
resembling Bacterium, Micrococcus, Spirillum, and Spiro-
chseta.

H. Kurth (Berichte Deutsch. Bot. Gesell., i., 1883, pp.
97-99) not only traced the growth of his Bacterium Zopfii
from leptothrix into rod and coccus forms, but also
determined the conditions under which one or the other
is produced — the rods being the vegetative and the coccus
the resting stage.

H. Zukal (Osterr. Bot. Zeitschrift, xxxiii., 1883, p. 73)
connects Bacillus subtilis, not only with Leptothrix parasitica,
but also with the Algae L. muralis and Drilosiphon Julianus,
Zuk. These observations seem to be founded upon errors.

E. Klein (Quart. Jour. Micr. Sa'., 1883, p. 260)
describes a torula-like variety of Bacillus anthracis, which
passed, sometimes even upon the same filament, into the
typical Bacillus. Similar forms of Bacteria have been
described by many others. Klein's growth, however, judg-
ing from his figures, does not resemble a true Saccharo-

Classification of the Schizomycetes. 73

myces. The word "Torula," like "Vibrio," is very much
misused by non-botanists. The true Torula belongs to the
Hyphomycetes.

F. Neelsen ("Neuere Ansichten iiber die Systematik
der Spaltpilze," Biolog. Cenlralblatt, iii., 1883, p. 545) gives
a review of the present state of the question, and confirms
Zopf's conclusions.

The most exhaustive account of the new views is con-
tained in Zopf s " Spaltpilze," in Schenk's " Encyclopadie
der Naturwissenschaften," 1883. We will first give a con-
densed account of his previous observations. Taking first
Cladothrix dichotoma, he found that the pseudo-dichotomous
threads resolve themselves by transverse division into short
cylindrical cells, which round themselves off by degrees
and then represent Micrococci. These Zopf compares to
gonidia. From these, after separation, short rods (Bacteria)
are evolved, which again, by continuous growth in length
and the formation of transverse septa, produce Bacillus-
like threads, which ultimately resemble Leptothrix para-
sitica, Kiitzing. These threads, like the Cladothrix, are
surrounded by a delicate gelatinous sheath which takes up
iron compounds from the water in which it lives, and thus
puts on the appearance of L. ochracea, Kiitzing. From this
the typical Cladothrix is produced again by false branching.
Moreover, small fragments break off and swim about, and,
under certain circumstances, bend into a spiral ; these spiral
forms are always articulated, and their elements are either
rod or coccus like. The height and breadth of the spirals
are very variable, as well as the thickness of the threads, and
some forms resemble Vibrio, others Spirillum and Spiro-
chaeta. The zoogloea form, of even more than one kind, is
also met with in Cladothrix.

Zopf also investigated Beggiatoa alba, Vaucher, which,

74 Synopsis of the Bacteria and Yeast Fungi.

in its Leptothrix form, after reaching a certain length,
shows a slow oscillating movement. At the ends of the
threads Micrococci arise, which unite in a zoogloea and
also grow into rods ; pieces of the end of the Beggiatoa
grow crooked, fall off, and form Spirillum-like fragments,
which swim about by means of flagella.

Again, Beggiatoa rcseo-persicina, Zopf {Cohnia roseo-per-
sicina, Winter), also forms Micrococci ; these cocci are of
two sizes, which grow genetically one from the other. From
the cocci grow threads of very varied lengths. Similar
results obtain in Crenothrix.

These three genera, Cladothrix, Beggiatoa, and Creno-
thrix, with Leptothrix, form the highest developments of the
Schizomycetes ; in them a distinction can be made out
between base and apex. The mode of vegetative multipli-
cation in this class of Fungi is always by bipartition (from
which circumstance, indeed, the name is derived) ; this
bipartition usually takes place in one direction, but occa-
sionally in two or even three. The cells are always enclosed
in a cell-wall ; this wall is usually composed of cellulose,
but in a certain group, viz. the putrefactive Bacteria, it
consists of a substance not much different from the cell-
contents, to which the name of mycoprotein has been given.
This shows a deviation from the vegetable cell in the
direction of the animal cell, and accounts for the discre-
pancies between earlier observers, some of whom, e.g. Dr.
Letzerich, always succeeded in obtaining the ordinary
cellulose reaction (a blue coloration with iodine and sul-
phuric acid), while others always failed. All the genera,
except the filiform ones, may be provided with flagella. The
reproduction by spores has been observed, not only in
Bacillus, but also in other forms, e.g. by Van Tieghem in
Leuconostoc, Spirillum, Spirochaeta, and Bacterium. There

Classification of the Schizomycetes. 75

is mostly only one spore in each cell. The zoogloea forms
are produced by aggregation, combined with the same
tendency of the cell-walls to gelatinise which is found in
many of the lower Algae,

As the result of his observations, Zopf proposes the
following classification : —

I. COCCACE^E. Possessing only the (micro-)coccus form, and the

thread form which arises from the juxtaposition of the cocci in

a line ... ... ... ... ... Leuconostoc

II. BACTERIACE^E. Possessing four forms, cocci, bacteria (short

rods), bacilli (long rods), and leptothrix threads. The last
show no distinction between base and apex. No spirak

Bacterium, Clostridium

III. LEPTOTRICHE.'E. Possessing five forms, cocci, bacteria, ba-
cilli, leptothrix (which last shows a distinction between base
and apex), and spiral forms

Leptothrix, Beggiatoa, Crenothrix, Phragmidiothrix

IV. CLADOTRICHE^E. Possessing coccus, rod, thread, and spiral
forms. Threads provided with false branching (pseudo-dicho-
tomy) ... ... ... ... ... Cladothrix

There is one more development of opinion with respect
to the Schizomycetes of which mention must now be made.
The belief is gaining ground that, among the lowest forms
of vegetal life, no such sharp distinction as hitherto can
be drawn between those which contain chlorophyll (the
algal series) and those which do not (the fungal series).
This view, which is embodied in the classification adopted
by Sachs in the later editions of his text-book of Botany,
is approved by Cohn (see Quart. Jour. Micr. Sri., 1876,
pp. 275, 276), and is now supported by Zopf himself.
According to the latter, such Algae as Glaucothrix and
Gliothrix, etc., show Chroococcus-like stages of develop-
ment which answer to the Micrococcus stage among the
Schizomycetes. The tendency of both to aggregate in
gelatinous colonies has been already adverted to. More-

76 Synopsis of the Bacteria and Yeast Fungi.

over, Van Tieghem and Engelmann describe (see infra, p. 88)
bacterioid forms containing chlorophyll, and the resemblance
between Beggiatoa and Oscillaria, both in form and in the
characteristic oscillating movement, is so great that some
botanists do not yet separate them. Again, Leuconostoc
differs from Nostoc solely in the want of chlorophyll, the
very peculiar formation of the spores being alike in both.-
Compare also Cohnia with Clathrocystis. The two kinds
evidently form two parallel series, which may conveniently
be united under the name of Schizophyta, being called
Schizophycese and Schizomycetes respectively. They are,
nevertheless, physiologically so distinct that there are
decided objections to interweaving them in one series, as
Cohn proposed. It would seem to be proved that, in all
cases where oxygen is given off during vegetable growth,
chlorophyll is present ; Rostafinski at one time believed
that Hasmatococcus dissociated carbonic anhydride without
chlorophyll, but it is now known to be present in that Alga,
though masked by the red colouring matter.

There may, perhaps, be detected, in the recent spread
of Zopf's views upon the pleomorphy of the Bacteria, a
little of that rage for "following the fashion," which is
almost as rife among scientific men as in the outer world.
A review of what has taken place in similar cases before
will teach the necessity of caution. When the swarm-spores
of Algae were first discovered, it was prophesied by Siebold
that most of the green moving Infusoria, described by
Ehrenberg, would be found to be only similar stages of
other algal forms. But this prophecy has not been fulfilled.
Again, when the doctrine of the pleomorphy of the Muco-
rini was first started by De Bary, it was eagerly seized upon
and its scope rapidly extended by rash observers, until in
the writings of some authors there was a confusion of species

Classification of the Schizomycetes. 77

almost incredible. One writer, Carnoy, even carried the
doctrine to the only rational conclusion which could be
deduced from such kind of observations as then existed :
he assertecLthat every species of Fungus, cultivated under
suitable conditions, could be transformed into Penicillium !
But later investigators, e.g. Van Tieghem, throw grave
doubts upon the accuracy of even De Bary's observations,
and he himself (" Beitrage," iv. i) seems to admit that he
was mistaken.

There are, however, many cases of pleomorphy in Fungi,
which may be considered as proven. We have only to refer
to the recent victorious establishment of the pleomorphism
of the Uredines, and it is natural to expect that similar
cases exist in other groups. But here we may learn another
lesson. Not every Puccinia passes through the three stages
which are typical of a Uredinous fungus; some occur in
one form alone, so far as our present knowledge goes. The
same may be expected to be the case with the Schizomy-
cetes. Even if we grant that some of them do pass through
a number of different forms, which have been hitherto
described as genera, it need not be inferred that there are
no distinct Micrococci, no independent Spirilla. In fact,
as evolutionists, considering that we are here dealing with
the simplest forms of life, we might anticipate that many
of the species would remain permanently, by arrest, in forms
which are mere stages of development of those more highly
evolved. Moreover, though one stage of Cladothrix dicho-
toma may resemble Bacterium Termo in outward form, as
Zopf asserts, it by no means necessarily follows that they
are identical. There may be differences between them of
which we have as yet no cognisance, for little is known
of the internal constitution of the Bacteria. What is
wanted now is a thorough and searching investigation of all

78 Synopsis of the Bacteria and Yeast Fungi.

the so-called species, in various media and under varying
circumstances, with the aid of all the modern refinements
for keeping the cultivations pure.

There is still another speculation to which the facts
appear to lead the way. A species such as those investi-
gated by Zopf is called a " Protean " species, and the
various forms are considered to be a series of adaptations
to the environment. Nageli, as we have seen, carried the
theory so far as to assert that there are no real species
among the Schizomycetes ; and Buchner considered that
he had transformed the harmless Bacillus subtilis by cultiva-
tion into the virulent B. anthrads, although his conclusions
are controverted by Cohn, Klein, and others. Much of the
disputation on this topic of " species " arises from the fact
that many persons cannot readily conceive a species in the
new light which the Darwinian theory has thrown upon it.
There can be no doubt that new species not only may, but
actually must, be making at the present moment. It is not
generally recognised that, to our floriculturists, the making
of what would, if spontaneous, be universally considered a
new species has been a frequent occurrence. Not only is
it probable that B. anthrads was developed from B. subtilis
(whether Buchner's conclusions be true or false), but man,
by a change of environment if continued long enough,
may at any time produce a similar change in another species.
During the siege of Paris, small-pox continued its ravages,
gradually assuming a more virulent and malignant form ;
the cause of this can only be that the micro-organism of
small-pox was changing its physiological nature, and, had
the conditions been constant for a sufficient length of time,
it might ultimately have formed what would be to all
intents and purposes a new species. Pasteur's "cultiva-
tion" of disease-germs in order to reduce their virulence

Classification of the Saccharomycetes. 79

is only an application of the same principle in the opposite
direction.

It follows (i) that we must consider as a species any
form or group of forms which, under present conditions,
can be clearly distinguished from all other forms, even
though we may know that, if the environment were changed,
the species would change too ; and (2) that species must
necessarily be of various ranks and of various degrees of
definiteness, as indeed we know to be the case. And in no
part of the scale of organised beings should we expect to
find clearer proof and more frequent examples of this
doctrine than among the lower Algae and their derivatives,
the lower Fungi.

In conclusion, it may be remarked that neither Cohn
nor Zopf have put forward their rival systems as final. At
the time of its promulgation Cohn's first arrangement was
indeed the only possible one, but he never asserted that
all the forms which he catalogued would be found to be
true and independent species. Zopf, on the other hand,
does no more than devise a system in which certain newly
discovered facts may find adequate representation ; but he
does not pretend that it will include all Schizomycetes.
The ultimate classification will probably be a compromise
between the two, though the exact form which it will assume
it is at present impossible to foresee.

The classification of the Saccharomycetes is in as un-
decided a state as that of the Schizomycetes, but in a some-
what different way. In this case also there are the two
opposing parties — one holding that most of the forms which
have been described in Chapter II. are independent species ;
the other, that they are for the most part only phases of
growth of one or a few species ; but the third view, which

8o Synopsis of the Bacteria and Yeast Fungi.

in the case of the Schizomycetes has attracted but little
notice, viz. that they are not autonomous Fungi at all, but
merely stages of development of species belonging to other
classes, finds here a numerous and active following.

Max Reess ("Zur Naturgeschichte der Bierhefe," 1868,
and " Botanische Untersuchungen iiber die Alkoholgah-
rungspilze," 1870) is one of the most conspicuous upholders
of the first doctrine, and his opinions are adopted by
Dr. Winter. Hallier and Hoffmann had previously put
forward the same doctrine of pleomorphism with regard to
the Saccharomycetes which they held for the Schizomy-
cetes ; and the latter, in a treatise, " Ueber Bacterien," in
the Botanische Zeitung (1869, p. 305), maintained, as so
many others have done, that the Yeast Fungi are derived
from the Moulds ; Penicillium and Mucor Mucedo were
the most generally credited with being the source from
which they originated. Many other Fungi are now known
to have stages of growth in which they simulate the Saccha-
romycetes. Quite recently, however (" Botanische Unter-
suchungen," heft v., 1883), Oscar Brefeld has elaborated
a comparatively new line of investigation in this respect,
and, as no account of his researches has to my knowledge
appeared in an English dress, they may be shortly abstracted
here. It must be premised that it is impossible to feel
much confidence in the results at which he arrives, as he
can be convicted of gross carelessness in many parts of his
previous work, and the present long and tedious treatise is
filled ad nauseam with peevish contentious disputations
against De Bary and Van Tieghem and all others who differ
from his opinions.

Brefeld considers that the conidia of various species of
Ustilaginese exactly resemble in mode of growth many of
the forms of the so-called Saccharomyces. It is well known

Classification of the Saccharomycetes. 81

that the spores of the Smuts, in germinating, protrude a
thread from which spring tufts or clusters of sporidia ; these
unite with one another by short transverse processes, and
then give rise to sporidia or conidia of the third generation,
and these to even a fourth kind. Brefeld's theory is that
these successive generations of conidia do not merely
resemble Saccharomycetes, but are identical with them. He
cultivated the spores of many Ustilagineae in nutrient fluids,
and found that the conidia to which they gave rise were
in form and dimensions similar to those of the various
Yeast Fungi — those of Ustilago antherarum being ovate ; of
U. Carbo, oblong-ovate ; of U. maydis, fusiform ; of U. be-
tonicce, cylindrical ; of U. Kuhniana, small and roundish ;
of U. cruenta, filiform ; and so on. Moreover, he cultivated
these sporidia in suitable media for numerous generations,
and found that they reproduced themselves, so long as
the conditions remained unaltered, with unfailing certainty
the whole year through. A pair of Smut spores was
induced to germinate, and the conidia which they produced
were transported, with due precautions, into a drop of
nutrient fluid, in which they continued to bud till the nutri-
ment was exhausted. A few of these were then removed
to another drop of the same fluid, and the process was
continued for nearly thirty times, extending over a space of
twelve months. The author considers that he has thus
proved that these conidia can propagate themselves inde-
finitely by budding, just like the cells of Saccharomyces, and
he asks, " If we had commenced this series of cultivations,
not with the Smut spores, but with the conidia which arise
from them, should we have been able to distinguish their
mode of growth from that of the yeast of beer ? "

"As to the other morphological character of the Sacchar-
omycetes, the endogenous formation of the spores, Brefeld

G

82 Synopsis of the Bacteria and Yeast Fungi.

considers truly enough, that this is more closely related
to the formation of spores in the sporangia of Thamnidium,
Chaetocladium, and Choanephora, than in the asci of the
Ascomycetes, and that it is exactly paralleled by the forma-
tion of zoospores in the conidia of some species of Perono-
spora and Cystopus, and that similar phenomena are met
with in the Gymnoasci.

With respect to the physiological character of exciting
alcoholic fermentation, Brefeld says very little, but since
the Mucor-ferment as well as other Fungi is said to possess
the same property, it would seem, if all these considerations
prove to be true, that the Saccharomycetes will have small
claim to autonomous rank. To what species, however,
if any, they must severally be attached, as budding conidia,
remains to be determined. For the present, all this is mere
speculation, and the only philosophic course is to treat
them as independent Fungi, until the contrary is fully
demonstrated. The authors who jumble up together Micro-
coccus, Mucor, Ustilago, Penicillium, Aspergillus, Oidium,
Torula, and Saccharomyces are not the true friends of
scientific progress.

83

CHAPTER IV.

PROTEAN AND LITTLE-KNOWN SPECIES.

THE present chapter will include those described Schizo-
mycetes which are inadequately known, or the true bacterial
nature of which is undecided, together with those Zopfian
species which could not be placed in the Cohnian classi-
fication.

BACTERIUM.

93. B. Zopfii, Kurth (Ber. Deutsch. Bot. Gesell., i.,
1883, pp. 97-99, pi. iii.).

Observed in three forms, long leptothrix threads, rods,
and cocci. In the fluid nutrient material at 20° C. the
rods passed into a swarming stage, and at 35° C. the swarm-
ing motion ceased, and short oscillating threads were
formed. When the nutrient material was nearly exhausted,
the threads broke up into rods, and when it was quite
exhausted, each rod divided into two cocci, which for the
most part remained united in a figure of eight. When
placed in fresh nutrient material, the cocci grew again into
rods. Division of the cocci was never observed ; they were
round or slightly oval, and i-i'25 /u, in diameter.

In the vermiform appendage of two hens which had died
of an epidemic disease. The threads were distinguished by

84 Synopsis of the Bacteria and Yeast Fungi.

their unusual length, forming long windings, and occasionally
close coils. It is interesting to observe that the stages of
development appeared to depend upon the quantitative
composition of the nutrient fluid, and that the rods were
the vegetative and the cocci the resting form. (Fig. 72.)

Fig. 72. — Bacterium Zopfii. a, a coil of leptothrix threads;
b, the same coil, nine hours later ; c, the same, thirty-seven
hours later than b; d, short rods, showing articulations,
X 740 (after Kurth).

94. B. merismopedioides, Zopf (Sitz.-Bericht. Bot.
Ver. Provinz Brandenburg, and " Die Spaltpilze,"
P- 56).

This species forms threads of i-i'S ^ in thickness.

These subdivide into long rods, then into short ones, and

finally into cocci, which have the same diameter as the

threads. The cocci pass through a motile

° 8 ® 8 §§ stage, and then subdivide, at first in one

by OD

Fig. 73.- Bacterium direction, and then in two, thus forming
merismopedioides t^e characteristic unilamellar plates, which

(after Zopf).

resemble Merismopedia. These colonies
may increase till they consist of 64 X 64 cells or more,
which finally form a zoogloea. The cocci develop again
into threads. (Fig. 73.)

In water containing putrefying substances.

Bacterium. 85

95. B. aceti (Kiitzing), Zopf.

Possesses (i) coccus forms, (2) short rods, (3) long rods,
(4) leptothrix threads; all four can form a zoogloea, the
two first also form^ swarms. It is characteristic that the
longer rods and threads
are not always cylindrical, OQ°O
but often provided with
irregular swellings. Such <==> °
forms have a rather thick- c;:^^::^"~!^O c-:i c— ' 00°°
ened membrane, and a Fig. 7^.— Bacterium aceti (after Zopf).
grey colour. (Fig. 74.)

Has the power of oxidising alcohol into acetic acid.

96. B. rubescens, Lankester (Quart. Jour. Micr. ,£/.,

1873, p. 408, pi. 22, 23).

Includes a series of forms, motile and immotile, which
resemble one another in the possession of a common
peach-coloured colouring matter, " bacterio-purpurin," which
sometimes becomes reddish-brown. The author observed
coccus, bacterioid, bacillar, acicular, and spiral forms, in
various modes of combination.

In a fresh-water aquarium in which crayfish (Astacus)
were decaying.

Cohn considers that Monas Okenii (q.v.), which is the form re-
presented by Lankester (I.e., pi. 23, figs. 12, 20), does not belong to
this life-cycle, and that the other forms belong to Cohnia roseo-persicina ;
this is now named by Zopf Beggiatoa roseo-persicina, because it possesses
a Beggiatoa phase, which is mentioned by Lankester himself in his
second article (I.e., 1876, p. 283). Archer also unwittingly records the
Eeggiatoa phase in the same journal. Geddes and Ewart describe
("On the Life-History of Spirillum," Proc. Roy. Soc., xxvii., 1878, p.
481) a madder-brown growth, which is evidently identical with Lan-
kester's, and in which they have observed and figured the Beggiatoa
phase, without perceiving its true significance, and mistaking also the
sulphur granules for " spores." Mixed with this was a Spirillum,

86 Synopsis of the Bacteria and Yeast Fungi.

probably belonging to the same life-cycle, in which true spores were
produced ; the germination of these, which they observed, took place by
the emission of a short curved tube, giving the spore a "comma "-like
appearance ; the tube soon became spiral. (See Spirillum rosaceum,
Klein, p. 94.) „

97. B. sulfuratum, Warming (I.e., p. 6 of the Resume").
Warming gives this name to a series of forms which

he discovered on the coasts of Denmark, all of which he
considers to be connected by intermediate stages. He
includes under it Monas vinosa, Ehrenberg, M. erubescens,
Ehrenberg, M. Warmingit, Cohn, and Rhabdomonas rosea,
Cohn, as well as spiral forms. His M. gracilis, moreover,
seems to differ merely in being more slender than Rhabdo-
monas, and was met with only in fresh water. All these
are of a pale pink colour, and contain numerous sulphur
granules. It appears to be distinct from B. rubescens,
Lankester, in all its varieties.

98. B. lactis, Lister (Quart. Jour. Micr. Sci., 1873,

pp. 380-408).

Includes coccus, bacterioid, bacillar, leptothrix, and
saccharomycetoid forms, motile and immotile, which the

Fig. 75.— Bacterium lactzs, X 1140 (after Lister).

author obtained by pure cultivation of the Bacterium that
appeared spontaneously in milk kept in a dairy. The
long rods appear to be formed by segmentation of the lepto-
thrix threads, these subdivide into short rods, and these into

Bacterium. 87

cocci ; the cocci can grow again into threads. The cocci
are about '5 /A in diameter, mostly in pairs or fours, or in
chains; the rods and threads 1-25 p, in diameter. (Fig. 75.)
Producing the lactic acid fermentation in boiled milk.
Resembles Bacillus subtilis, (?) identical. This is interesting,
as being one of the earliest observations of pleomorphism
in the Schizomycetes.

99. B. fcetidum, Thin (Proc. Roy. Soc., xxx., 1880,

p. 473, pi. 6).

Occurred as Micrococci, singly or in pairs, 1-25-1 -4 /x,
in diameter. On cultivating them, with proper precautions,
he found also short and long rods,

and leptothrix threads, and all the °<^f> ^ /*2 £**
stages of transition between these x> \ E *
and the Micrococci. In the rods, Fi&- 7*-— Bacterium fcetidum,

Xgoo after Thin).

oval spores about i'5 /x long were

formed, one at each extremity of a cell, as in Bacillus.

(Fig. 76.)

In the alkaline serous exudation from the soles of the
feet of a person who suffered from profuse sweating of
the feet, producing a foetid odour, also observable in the
cultivations, in which, however, it became gradually weaker.

100. B. decalvans, Thin (Proc. Roy. Soc., xxxiii. p.

247, pl- 3)-

Occurred as minute bodies, highly refractive, of a
definite size and fixed shape, about i '6 //. 0 g
long, usually in pairs. They became more •<,?* *
numerous as the hairs became worse affected
by the disease. (Fig. 7 7-) F^££

In and on the roots of the hairs in x 600 (after
Alopecia areata. Dr. Thin supposes that they Thin)>
penetrate downwards between the root-sheath and the hair,

88 Synopsis of the Bacteria and Yeast Fungi.

then penetrate the cuticle of the hair, and finally ascend
within its substance, causing it soon to fall off.

1 01. B. lucens, Van Tieghem (Bull Soc. Bot. France,

1879, p. 141).

Motionless, remarkable for its strong refringence and
brilliancy. Each cell forms a spherical spore.

On the surface of water containing other organisms.

102. B. photometricum, Engelmann (Revue Internat.

Sci., ix., 1882, p. 469).

Cells of a slightly reddish colour ; the author describes
neither their form nor size. The micro-spectroscope shows
a strong absorption of all the rays whose wave-length is
less than -62 /x, especially of those between -62 and '59
(orange). It is sensitive in a high degree to the influence
of light (For details, see Jour. Roy. Micr. Soc., 1882,
p. 656, and 1883, p. 256.)

103. B. chtlorinum, Engelmann (I.e., p. 276).

Cells 2-3 /A long, motile, of a greenish colour, paler
than that of a chlorophyll granule of the same size. It
presents in a high degree the tendency to accumulate in
the light, but only when oxygen is absent ; according to
the author, it disengages oxygen in the light, and is there-
fore not a Schizomycete at all.

104. B. viride, Van Teighem (Bull. Soc. Bot. France,

1880, p. 174).

Rods minute, of a pure green colour, constricted in the
middle, dividing frequently, and separating after each seg-
mentation, but otherwise immotile. In a large number of

Bacillus. 89

rods it forms spores, colourless, very refringent, of a
spherical or slightly oval form, like those of a Bacillus.

In the rain-water which filled the cavity of the pileus
of a young Polyporus, forming a thin layer.

This can scarcely be a Bacterium. The colouring matter, according
to Van Tieghem, is true chlorophyll. He compares it to B. lucens.

Wakker records (Bot. Centralblatt, 1883, p. 315) a Bacterium
resembling .#. Termo, causing the " yellow disease " of hyacinths. It
occurred in a yellow slime in the bulbs in autumn, and in the leaves
in spring. He calls it B. hyacinthi.

BACILLUS.

105. B, crassus, Van Tieghem (Bull. Soc. Bot. France,

1879, p. 142).

Cells motionless, large, resembling B. Ulna, 4 //. broad
during active growth, 5-6 p. when forming spores. Spores
spherical, 5 //, in diameter.

The spores of this species are the largest known among
the Schizomycetes. It does not produce starch.

1 06. B. malariae, Tommasi-Crudeli (Atti R. Accad.

Lincei, Trans., vi., 1881, p. 19).

In the spleen, the medulla of bones, the lymphatic
glands, and the venous blood of persons suffering from
malarial fever. The evidence of the existence of this
species is at present unsatisfactory.

107. B. puerperalis, Engel (Comptes Rendus, Ixxxviii.,

1879, p. 976).

In the blood of a woman who had died in childbirth.
Engel observed the production of conidia.

1 08. B. mollusci, Domenico (Atti R. Accad. Lincei,

Trans., v., 1880).

Resembling B. lepra. In the nodules of Molluscum
contagiosum.

90 Synopsis of the Bacteria and Yeast Fungi.

109. B. virens, Van Tieghem (Bull. Soc. Bot. France,

1880, p. 175).

? Leptothrix tenuissima, Rabenhorst.
? L. subtilissima, Rabenhorst.
? Sporonema gracile, Perty. (Fig. 78.)
Filaments slender, of a greenish-yellow colour, usually
immotile, but sometimes
moving; cells long, re-
sembling those of B. an-
thracis, forming a very

Fig. rf.— Sporonema. gracile (after Perty). refringCnt, OVal, Colourless

spore, slightly thicker than the threads. Spores in ger-
minating put forth a slender filament, soon septate, at first
colourless, but becoming green like the original threads in
the light

In stagnant water among Spirogyra.

Perty observed the spores of this species, if it is identical with his
Sporonema. It seems a doubtful Schizomycete.

no. B. beribericus, De Lacerda.

This has been discovered in the blood of patients suffer-
ing from the disease known in the tropics as beri-beri. It
consists of cylindrical, articulated, branched (?) filaments,
containing sometimes brilliant refringent points, which are
believed to be spores. The filaments cultivated after
Pasteur's method, with due precautions, and injected into
rabbits, caused all the symptoms of beri-beri. M. de
Lacerda believes that the parasite is originally derived from
rice which has undergone a peculiar alteration (Lancet,
February 9, 1884, p. 268).

Bacillus of Cholera.

The Commission sent out by the German Government,
under Dr. Koch, has observed in the bodies of cholera

Bacillus. 91

patients in India, in every case, the same Bacilli that they
found in Egypt. But it was still undecided whether these
Bacilli did not belong to the regular parasites of the gut,
having made their way into the mucous membrane of the
intestine under the influence of the cholera disease. Some
of the Bacilli were, therefore, isolated from the intestinal
contents of the purest cholera cases and cultivated in
gelatine, so as to investigate their distinctions from other
Bacilli. In this way it was demonstrated that this kind of
Bacillus was present in all the choleraic evacuations ex-
amined, as well as in all the intestinal contents from persons
who had died of cholera. On the other hand, the bodies
of eight persons who had died of pneumonia, dysentery,
phthisis, and kidney-disease were examined, as well as the
bodies of several animals, and other substances abounding
in bacteria, but in none of these cases was the cholera
Bacillus found. It is also reported that the same organism
was discovered in water from a tank, which had been
suspected of being a source of the disease.

Bacillus of Syphilis.

Despite the strenuous efforts which have been made
to demonstrate the existence of a specific Bacillus of
syphilis, it must be admitted that the evidence is as yet
inconclusive.

There are also described the Bacillus of the pneumo-enteritis of the
pig (Klein, Proc. Roy. Soc., xxvii. p. 101), which resembles .#. anthracis,
but differs in the cylindrical spores, which measure only '5 /j. in length ;
the Bacillus of malignant oedema (Koch) ; B. urea (Miquel) ; and a
Bacillus in a badger's liver (Eberth).

92 Synopsis of the Bacteria and Yeast Fungi.

DISPORA.

in. D. Caucasia, Kern (Bot. Zeitung, xl., 1882,
p. 264).

Cells resembling B. subtilis, 3*2—8 p. long, '8 p, broad,
with a flagellum at each end. Forming long leptothrix
threads by growth and cell-division, and then producing
spores, which "stand on their ends," two in each cell
Spores round, '8 /*, in diameter, afterwards increasing to i /A.

In " kephir," a drink prepared by the inhabitants of the
high-lying lands of the Caucasus, by fermentation of cows'
milk. (See Nature, 1882, p. 43, xrAJour. Roy. Micr. Soc.,
1882, p. 383.)

This may be the result of mal-observation. In B. subtilis, when a
cell is elongated, and about to divide, two spores are sometimes found
in one cell.

BEGGIATOA.

112. B. nodosa, Van Tieghem (Bull. Soc. Bot. France,
1880, p. 176).

Filaments colourless, very slender, motionless ; articula-
tions shorter than broad ; no sulphur granules. At intervals
some of the cells become more refringent, enlarge, and
persist like spores, and form nodosities on the filament
Similar monstrosities exist, according to Van Tieghem, in
true Oscillarias. This is not a true Beggiatoa.

PHRAGMIDIOTHRIX, Engler.

Differs from Beggiatoa in the want of sulphur granules
and the continuous subdivision of the cells, and from
Crenothrix in the want of a sheath.

Leptothrix. 93

113. P. multineptata, Engler ("Pilz-veg. weiss. oder

todt. Grundes in der Kieler Bucht ").
Beggiatoa multiseptata, Engler (Sitz.-Bericht.
Bot. Ver. Provinz Brandenburg, 1882, p. 17).
Threads 3-6 fj. broad, separated by transverse partitions
into short cylinders, whose height is only one-fourth to one-
sixth of their breadth. These discs are separated by re-
peated transverse and longitudinal division into cocci,
which probably become isolated. From these cocci very
slender threads arise which afterwards become thicker.
Attached to the legs of crabs (Gammarus) in sea-water.

LEPTOTHRIX.

114. L. gigantea, Miller (Ber. Deutsch. Bot. Gesell.,

1883, pp. 221-224, pl- vi.).

Occurred as bundles or tufts of diverging threads, which
varied very considerably in thickness in the same tuft, from
•5-4 p.; threads 250 p. long or
more, showing a distinction
between base and apex, the
thicker ones consisting of
articulations, which formed
cocci, short rods, or long
rods, sometimes all in the
same thread. Some of the
threads showed a sheath, from

i-- u ^u T • j FiS- 79-— Leptothrix gigantea. a, base

which the articulations passed of a tuft of threadSj x 540. b> stages

OUt, Collecting in a heap at of. subdivision of the threads (after

the extremity. Articulations

round, oblong, or pear-shaped ; the larger ones dividing into
smaller, first by a transverse and then by a longitudinal
septum. Some of the threads assumed a spiral form, and
even approached Spirochaete. (Fig. 79.)

94 Synopsis of the Bacteria and Yeast Fungi.

In the teeth of a dog suffering from Pyorrhoea alveolaris,
and subsequently in the bite of other carnivorous and her-
bivorous mammals, sheep, cattle, pigs, horses, cats, etc.
The subdivision of the larger cocci and the septation of
the finer threads were only made visible by staining.

This is considered by Miller as affording a very strong proof of the
truth of ZopPs theory. It resembles Beggiatoa alba and Crenothrix
Kiihniana. Miller also found the same stages in L. buccalis (see
Fig. 2"ja) in carious teeth ; in this the cocci penetrated into the tooth
more deeply than the rods, and they in turn than the longer threads
(supra, p. 72). It is to be remarked, however, that what are here
called cocci, rods, and spiral forms are not the exact counterparts of
typical Micrococci, Bacteria, and Spirilla. (See also F. Y. Clark, in
Johnston's Dental Miscellany, 1879, p. 447, who describes a Bacterium
in the teeth, 1*5-3 /* long, *5 /* broad, of a somewhat spiral form.)

SPIRILLUM.

115. S. rosaceum, Klein (Quart. Jour. Micr. Set'., xv.,

1875, p. 381).

Resembling S. Undula, but reddish in colour ; colour-
ing matter insoluble in water, alcohol, or chloroform.

Seems to be identical with S. rufum, Perty (Prit chard,
" Infusoria," p. 534), and possibly not different from the
form recorded by Geddes and Ewart (Proc. Roy. Soc., 1878,
p. 482). It is distinct from S. sanguineum, Cohn, with which
it has been confounded (see also Bacterium rubescens, p. 85).

1 1 6. Spirulina alba, Van Tieghem (Bull. Soc. Bot.

France, 1880, p. 177).

Absolutely colourless. Filaments very long and slender,
resembling S. tenuissima. Coils so close together as almost
to touch and form a hollow tube. Turning actively round
its axis, and also oscillating laterally as a whole.

Forming a thin white layer on the muddy bottom of

Cryptococcus : Sarcina. 95

an abandoned mill-race. This, if the want of colour were
not accidental, would appear to be a Schizomycete.

CRYPTOCOCCUS.

117. C. xanthogenicus, Freire.

Resembling a Micrococcus. Said to have been dis-
covered iri Brazil, in persons suffering from yellow fever.

Dr. Freire, having .cultivated this in gelatine for six
generations, says that, when introduced into the body by
" vaccination," it produced a mild type of yellow fever ; he
had previously observed that rabbits and guinea-pigs, so
inoculated, were proof against the fatal type of the disease.

Micrococcus sp. W. Archer describes (Quart. Jour.
Micr. Sa'., xiv., 1874, p. 321) a "black" Micrococcus, really
blue-black, consisting of cells rounder than in M. prodigiosus,
arranged in twos or fours, the latter in a square, not in a
straight line.

SARCINA.

1 1 8. S. solani, Reinke et Berthold ("Die Zersetzung

der Kartoffel durch Pilze," p. 22, pi. vii. fig. 13).

Cells small, colourless, round or before division oval;
some free, others collected in unilamellar
colonies of from 4 to 24; i'3~2 p in
diameter. (Fig. 80.)

In rotting potatoes. (See Bacterium
merismopedioides, Zopf, supra, p. 84, with
which this seems to be identical.)

I have found a very similar Schizomycete in Fig. 80. — Sarcina solani.
putrefying starch-paste, which differed in scarcely a> side view of 'wo

any respect except its much larger size, the £la.tef' X , 14° , ^ftfr
, . n i_ • j JZTO Reinke and Berthold).

colourless cells being perfectly round and 6-8 ju

in diameter. It occurred singly or in pairs or fours, always unilamellar,
the tetrads being collected together in families of 16, 24, or more cells.

96 Synopsis of tlie Bacteria and Yeast Ftmgi.

POLYBACTERIA, Van Tieghem (Bull Soc. Bot.
France, 1880, p. 149).

Under this and the following genera, Van Tieghem
places some bacteria which are probably only zooglcea
stages of other species, like Ascococcus, which they
resemble.

119. P. catenata, Van Tieghem (I.e., p. 150).
Colonies naked, oval, colourless, composed of short

rods aggregated without order; the colonies divide trans-
versely in such a manner as to remain attached end to end
in a flexuous chain.

In a decoction of horse-dung.

120. P. sulfurea, Van Tieghem (I.e., p. 150).
Colonies rounded or polyhedral, composed of short

rods of a sulphur colour ; the colonies divide in two direc-
tions at right angles to one another, so as to form a simple
layer.

On the surface of a liquid in which haricot-beans were
decaying.

PUNCTULA, Van Tieghem (I.e., p. 150).
Differing from Polybacteria, in the cells of which it is
composed being round.

121. P. rosea, Van Tieghem (I.e., p. 150).

Colonies single, of a bright rose colour, spherical ; cells
round, extremely small, arranged in radiating lines and
concentric circles.

122. P. cubica, Van Tieghem (I.e., p. 150).
Colonies cubical, dividing successively parallel to each

Ascobacteria : Ascococciis. 97

face, so as to form cubical masses. Cells rather larger than
in P. rosea, colourless, round.

123. P. glomerata, Van Tieghem (I.e., p. 150).
Colonies rounded, colourless, dividing in three direc-
tions, and remaining associated in lobed masses.

All three forms were met with on putrefying seeds.

ASCOBACTERIA, Van Tieghem (I.e., p. 151).

This consists of colonies surrounded by a thick gelati-
nous membrane, and bears the same relation to Polybacteria
that Cohn's Ascococcus does to Punctula.

124. A. ulvina, Van Tieghem (I.e., p. 151).

Colonies polyhedral, enveloped in a thick cartilaginous
membrane, forming a coherent membrane like an Ulva,
composed of short rods aggregated without order, which
increase by bipartition.

On the surface of liquids in which leguminous seeds,
especially of lupin, were decaying.

ASCOCOCCUS, Cohn.

125. A. vibrans, Van Tieghem (I.e., p. 151).

Similar to A. Billrothii, but the cells oscillated and
whirled round, as in the Brownian movement.

On the surface of water in which Beggiatoa was
growing.

All these aggregated bacteria of Van Tieghem live on
the surface of fluids, and often, if not always, disengage
ammonia, like Ascococcus.

H

Synopsis of the Bacteria and Yeast Fungi.

MONAS.

The following species, placed under Monas, are con-
sidered by Warming to belong to the Schizomycetes : —

126. M. vinosa, Ehrenberg ("Die Infusionsthierchen,"

p. n).

Chromatium violascens, Perty.

Cells ovate, rounded at each end, very small, 2-4 p., of
a wine-red colour. Motion very slow and
•®^ $ Q '/&'' tremulous.

&@°Q © %• The form which Warming considers

(fo &> jj identical with this is spherical or more
commonly oval, -5-4 /u, in length, pinkish-
red, granular, actively motile, with a
flagellum. (Fig. 81.)
In water containing decaying vegetable matter.

Fig. 81. — Monas -vi-
nosa(f)-X. 660 (after
Warming).

127. M. Okenii, Ehrenberg (I.e., p. 15).

Chromatium Weissii, Perty.

Cells cylindrical, equal, slightly curved, abruptly rounded
at each end; 7—15 p- long, but, according to Warming,
much longer, 5 /*, broad, of a bright
red colour, motile; the granules are
pretty evenly distributed throughout
the body ; furnished with a flagellum,
in the large specimens one at each
end. Movements slow. (Fig. 82.)

In stagnant water. According to
L. Olivier (Bull. Soc. Bot. France, 1882,
p. 216), M. Okenii, which Lankester
admitted to be one of the forms described by him under
Bacterium rubescens, is not a Schizomycete, but a true monad,

Fig. 82.— Monas Okenii,
X 660 (after Warming).

Monas. 99

destitute of ternary envelope, and he places it among the
Nudo-flagellata.

128. M. Warmingii, Cohn.

Cells cylindrical, rounded at the ends,
pinkish, with the granules accumulated at
the extremities; 15 ft long, 5-6 /* broad
(according to Warming), 8 /A (Cohn), with
a flagellum. Movements rapid, but irregu-
lar. (Fig. 83.)

In brackish water.

129. M. erubescens, Ehrenberg (I.e., p. n).
Warming considers this identical with

M. Warmingii, differing only in having the
granules equally distributed; 14 //. long,
6-7 /A broad.

In brackish water.

130. M. gracilis, Warming (I.e., p. 6

of the Resume").

Cells straight, cylindrical, slender,
rounded at the ends, pinkish; 60 p. long
or less, 2 //. broad ; paler than M. Okenii,
with few sulphur granules. Movements T,.

Fig. 84.— Manas gra-

slow ; sometimes slightly curved. (Fig. 84.) «/», x 660 (after
In fresh water. Warming).

131. M. Mulleri, Warming (I.e., p. 18 of the Resume').

Volvox punctum, Miiller.

Cells spherical or oval, 5-6-15 fi long, having usually
one extremity filled with angular and very refringent
granules, the other empty and hyaline. Granules whitish,

ioo Synopsis of the Bacteria and Yeast Fungi.

with a blue tinge and a dark border. Movements inces-
sant. A flagellum (?). (Fig. 85.)
In sea-water.

132. M. fallax, Warming (I.e., p. 18 of the Resume").
Cells small, 4-5 /u. long, 3 p. broad, oval, sometimes

Fig. Bs.-Monas MUlleri, Fig. to.— Mono* fallax,

X 660 (after Warming). X 660 (after Warming).

curved or angular, and almost entirely filled with crystalline
and very refringent granules. Movements rapid. (Fig. 86.)
Warming considered that some of these monads may be the
zoospores of Beggiatoa.

133. Rhabdomonas rosea, Cohn.

Cells fusiform, pinkish, granular; 20-30 /* long, 4-5 p.
broad. Movement slow ; with
a flagellum. (Fig. 87.)

Some of Warming's speci-
mens were cylindrical, 3-4 /x
broad, 15-35 /"• l°ng> or more ;

Fig. Zj.-Rhabdomonas rosea, X 600 but he figures Spindle-shaped
(after Cohn).

forms as well.
In brackish and fresh water.

APPENDIX A.

ON THE UNIT OF MICROSCOPICAL MEASUREMENT.

IT has for some time been the general practice on the
Continent, and is beginning to be so in England, to give the
dimensions of microscopic objects in terms of a thousandth of a
millimetre, which is called a micro-millimetre, and is variously
designated by the abbreviations jt, mk., and mmm. The first
abbreviation, being the shortest, is the most generally adopted ;
but there seems still to be a prejudice existing against this unit,
from a want of knowledge of the advantages which its use
confers or of the mode of using it. In the first place, it is
always easier to conceive the size of any object, and especially
to realise the comparative sizes of two objects, when their
dimensions are given in terms of a unit smaller than either ;
for instance, it is difficult exactly to comprehend the length
represented by ^ of an inch, and few people can readily
compare such dimensions as -^g and ^ of an inch.

All this difficulty vanishes when the dimensions are expressed
as multiples of a small, properly chosen unit, and not as
fractions of a large one. For this purpose a fraction of an inch
might be adopted instead of a fraction of a millimetre ; but, at
any rate in measuring the spores of Fungi, 10^00 of an
inch is too large a unit, and T0 0*000 of an inch would be
inconveniently small. It happens that, if we take ^^ of a
millimetre as our unit, we can express the size of the spores of
all Fungi, and also of many other microscopic organisms, in
the fewest possible figures. For instance, many of the Micro-

102 Appendix A.

cocci measure about i jt, the spores of Penicillium about 3 /u, the
spores of many Myxomycetes about 10 /a, and so on. If we
compare these figures with the following : 'ooi mm., '003 mm.,
•or mm., or still more with these : '00004 in., -coo 12 in.,
•0004 in., — we see the great saving effected in the trouble of
writing down the dimensions, quite apart from the greater
readiness with which they can be compared with one another.

But perhaps the difficulty with some is that of realising and
actually applying this unit ; I will therefore give an easy method
by which the size of the micro-millimetre may be obtained. Place
your microscope in such a position that the image projected
upon a piece of white paper is magnified 254 times : this can
easily be done by a quarter-inch objective with the use of the
draw-tube, or by placing the paper at a greater distance than ten
inches from the eye-piece. Let this position be marked, so
that the microscope can be placed in it again at any time-
Now copy on the paper, from a scale, an inch divided into ten
parts, and with a fine pen subdivide each tenth into five equal
parts. Then the value of each of these subdivisions will be 2 ^
and of the whole tenth of an inch, 10 /*. If this scale be care-
fully copied on a piece of thin cardboard or other suitable
substance, the dimensions of any minute object, drawn by the
camera or otherwise on the paper in that position of the
instrument, can be easily read off in /t's. With the aid of a
deeper eye-piece or higher objective we can magnify the image
508 times, and then each small division of the scale will re-
present i fji.

APPENDIX B.
ON THE STAINING OF "BACILLUS TUBERCULOSIS."

PROFESSOR KOCH (Verh. Physiol. Gesell., Berlin, 1882, p. 65)
first announced the discovery of the Bacillus of tuberculosis.
He placed the fluid from the diseased tissues in a mixture of

1 c. cm. of a concentrated solution of methylene blue in alcohol,
o'2 c. cm. of a ro-per-cent. solution of potash, and 200 c. cm. of
distilled water. By this the preparation is coloured blue, and a
few drops of a solution of vesuvin are then placed on it. This
discharges the blue from every part except the Bacilli, which
remain blue in a brown field, but are not easily seen.

Ehrlich's method, especially as modified by Heneage
Gibbes, is more successful. The colours used by the latter
are magenta crystals and chrysoidin, which is a brown that
does not stain the ground so intensely as vesuvin. (i) Take

2 grm. of magenta crystals, 3 grm. of pure aniline, 20 c. cm.
of alcohol (specific gravity, 830), 20 c. cm. of distilled water.
Dissolve the aniline in the spirit, and rub up the crystals with it
in a glass mortar, adding the spirit gradually till they are all
dissolved ; then add the water slowly, while stirring, and keep
in a stoppered bottle. (2) Make a saturated solution of
chrysoidin in distilled water, and add a crystal of thymol to
make it keep. (3) Make a dilute solution of commercial nitric
acid, one part of acid to two of distilled water. Spread a thin
layer of sputum on a cover-glass, and let it dry ; when quite dry
pass it two or three times through the flame of a small Bunsen
burner, and let it cool. Filter two or three drops of the magenta

IO4 , Appendix B.

solution in a watch-glass ; place the cover-glass, with the
sputum downwards, on the stain, taking care that there are no
air-bubbles under it. Let it remain for fifteen or twenty
minutes ; then wash in the dilute acid till all colour has dis-
appeared. Remove the acid with distilled water ; then place the
cover-glass in the same manner as before on a few drops of
chrysoidin, filtered into the bottom of a watch-glass, and let it
remain for a few minutes till it has taken a brown stain. Wash
off the superfluous colour in distilled water, and place the cover-
glass in absolute alcohol for a few minutes. Then remove and
dry perfectly in the air, and mount in a solution of Canada
balsam. The Bacilli are visible with a quarter-inch objective.
(See Lancet, ii., 1882, p. 183.) By this process only B. tuber-
culosis is stained, the ordinary putrefactive bacteria remaining
colourless.

Prideaux (I.e., p. 1138) uses methylene-blue instead of
chrysoidin for staining the ground ; by this means the Bacilli
show up red on a blue background. The process may fail if the
solutions are at a lower temperature than 100° F., and Professor
Brun recommends that the sputum should not be exposed to a
greater heat than 176° F. If gentian violet be used, after the
nitric acid treatment, the putrefactive bacteria will be stained,
and not the tubercle bacilli, which are thus strongly differ-
entiated. The latter are also stained by fuchsin.

The following is Heneage Gibbes's rapid method of demon-
strating B. tuberculosis without nitric acid. Take of rosaniline
hydrochloride 2 grm., methyl -blue I grm. ; rub in a glass
mortar. Then dissolve aniline oil 3 c. cm. in rectified spirit
1 5 c. cm. ; add the spirit slowly to the stain till all is dissolved ;
then slowly add distilled water 15 c. cm.; and keep in a stop-
pered bottle. Place a few drops of the stain in a test-tube,
and warm ; as soon as steam rises, pour into a watch-glass, and
place the cover-glass as before. After four or five minutes wash
in methylated spirit till no more colour comes away ; drain
thoroughly, and dry either in the air or over a spirit-lamp.
Mount in Canada balsam. A section of tissue containing Bacilli
can be treated in the same way, only it must be left in the stain
for several hours.

APPENDIX C.

DISEASES PRODUCED BY THE SCHIZOMYCETES.

THE following classification of the Schizomycetes and the
diseases produced by them, arranged according to Cohn's sys-
tem, was read before the British Medical Association, by Dr.
Julius Dreschfeld, in 1883 :—

I. SPH^ROBACTERIA (Micrococci) : spherical or oval cells, rather lessi
than i /* in diameter, occurring singly or in pairs (diplococci) or
in masses (zoogloea).

a. Chromogenous — M. prodigiosus.

b. Zymogenous — M. urea.

c. Pathogenous — In the following diseases : —

Acute abscess.

Pyaemia.

Septicaemia.

** Septicaemia in mice (Koch).
** Erysipelas.

Osteomyelitis.

Endocarditis ulcerosa.

* Diphtheria.
** Gonorrhoea.

* Pneumonia.

Cerebro-spinal meningitis (Aufrecht).

Cerebral meningitis (Leyden).

Acute yellow atrophy of liver.

Variola.

Scarlatina.

Measles.

Typhus (Mott).

'* Those diseases in which it is fully established that the micro-
organism is the causal agent ; * those in which it is less fully proved ;
the rest are doubtful.

106 Appendix C.

Syphilis (Birsch-Hirschfeld, Klebs).
Dysentery (Prior).
Whooping-cough (Burger).

II. MICROBACTERIA : small cylindrical or elliptic rods, occurring singly

or in pairs or in zoogloea masses.

a. Chromogenous — Bacterium synxanthnm (in yellow milk).

B. (zruginosutri (in blue pus).

b. Zymogenous — B. Termo (in putrefaction).

B. Lituola (in stagnant water).

Mycoderma aceti (in acetic acid fermentation).

c. Pathogenous — In ** Septicaemia of rabbits (Koch).

** Chicken cholera (Pasteur).
Typhus? (Klebs).

III. DESMOBACTERIA.

1. BACILLI : longer rods, often showing the formation of spores.

a. Chromogenous — Bacillus ruber (in boiled rice).

b. Zymogenous — B subtilis (in hay infusion).

B. butyricus (in butyric acid fermentation).

c. Pathogenous — In the following diseases : —
** Anthrax.

** Glanders.

** Septicaemia in mice (Koch).

Malignant oedema of animals and of man (Ehrlich).

Meat-poisoning in man (Klein).

Typhoid fever.

Malaria.

Diphtheria (Klebs).

Lepra.

** Tuberculosis (including tuberculosis, phthisis, scrofula,
lupus, and heart-disease of animals).

2. LEPTOTHRIX : longer rods and fibres, often occurring in bundles,

and found in the saliva, etc., L. buccalis.

IV. SPIROBACTERIA : threads forming spirals.

1. SPIRILLUM : spirals rigid ; S. serpens (in stagnant fluids).

2. SPIROCH^TA : spirals not rigid.

In the tartar, and in caries of the teeth.
** 5. Obermeieri (in relapsing fever).

Actinomyces, which is introduced into this list by Dr.
Dreschfeld, is a Hyphomycete, and does not belong to this class
of Fungi.

INDEX.

The references are to the pages. The names of genera and species
quoted as synonyms or mentioned in passing are printed in italics.

Bacillus of cholera, 90

of syphilis, 91

puerperalis, Eng., 89

ruber, F. et C., 33

subtilis, Cohn, 3, 27

suis, Detmers, 13

tremulus, Koch, 28

tuberculosis, Koch, 5, 45,

103

Ulna, Cohn, 30

ure<z, Miquel, 91

virens, Van T., 90

Bacteria, aggregated, 96
Bacteriacese, 75
Bacteridiumaurantiacum, Schr., 8

cyaneum, Schr., 9

luteum, Schr., 8

prodigiosum, Schr., 7

violaceum, Schr., 9

Bacterio-purpurin, 18, 85
Bacterium, 22, 75

aceti, Zopf, 85

seruginosum, Schr., 26

chlorinum, Eng., 88

decalvans, Thin, 87

fcetidum, Thin, 87

fusiforme, Warm., 25

griseum, Warm., 14

hyatinthi, Wakk., 89

lactis, Lister, 86

Lineola, Cohn, 24

Acetification, 65, 85, 106
Adinomyces, 106
Alcohol, 57
Alopecia, 87
Ammonia, 9, 15, 97
Anthrax, 30, 106
Aphtha, 66
Ascobacteria, 97

ulvina, Van T., 97

Ascococcus, 15, 96

Billrothii, Cohn, 15

mesenterioides, Cien., 16

vibrans, Van T., 97

B

Bacillus, 26, 89

Amylobacter, Van 71, 29, 50

anthracis, Cohn, 30

beribericus, De Lac., 90

crassus, Van T., 89

erythrosporus, Cohn, 33

formation of spores, 3

germination of spores, 4, 28

leprae, Hansen, 32

malariae, Tomm. , 89

mollusci, Dom , 89

io8

Index.

Bacterium litoreum, Warm., 24

Chromobacteriumviolaceum, Berg.,

lucens, Van T., 88

26

merismopedioides, Zopf, 84,

Chromogenous species, 5

95

Chroococcus, 75

Navicula, R. et B., 25

Cladothrix, 40, 75

photometricum, Eng., 88

dichotoma, Cohn, 41, 73

rubescens, Lank., 17, 85

Forsteri, Wint., 41

sulfuratum, Warm., 86

Clathrocystis, 17

syncyanum, Schr., 26

(Eruginosa, Henf., 17

synxanthum, Schr., 25

roseo-persicina, Cohn, 1 8

Termo, Duj., 10, 23

Clostridium, 75

triloculare, Ehr. , 24

butyricum, Prazm., 29

violaceum, Gr., 26

Coccacese, 75

viride, Van T., 88

Cohnia, 17

Zopfii, Kurth, 83

roseo-persicina, Wint., 17,

Beer, fermentation of, 59, 6l, 62

74

Beet-root sugar, 16

Consumption, 32

Beggiatoa, 36, 75

Crenothrix, 54, 75

alba, Trev., 36, 73
marina, Cohn, 37

Kiihniana, Zopf, 55
polyspora, Cohn, 55

arachnoidea, Rab. , 38

Cryptococcus

leptomitiformis, Trev., 38
minima, Warm. , 40

cerevisics, Kiitz., 58
fermentum, Kiitz., 58

mirabilis, Cohn, 39

glutinis, Fres., 63

multiseptata, Eng., 93

guttulatus, Rob., 66

nivea, Rab., 37

xanthogenicus, Freire, 95

nodosa, Van T. , 92

Cultivation, Pasteur's, 78

(Erstedtii, Rab., 37

pellucida, Cohn, 38

punctata, Trev., 36

D

roseo-persicina, Zopf, 18, 74»

85

Desmobacteria, 69, 106

tigrina, Rab., 39

Diphtheria, n, 105, 106

Beri-beri, 90

Diseases produced by Schizomy-

Blood-rain, 7

cetes, 105

Blue milk, 26

Dispora, 92

Butyric fermentation, 28, 29

Caucasia, Kern, 92
Drilosiphon Julianus, Zuk, 72

Dysentery, 1 06

C

Caries of the teeth, 35, 44, 94, 106

E

Carpozyma apiculatum, Eng., 62
Cellulose fermentation, 29

Erysipelas, 105

Chicken-cholera, 13, 1 06

Chinch-bug, 13

Chlorophyll, 88, 90

F

Cholera, 13, 90

Chromatium violascens, Perty, 98

Fermentation, i, 57, 64

Weissii, Perty, 20, 98

alcoholic, 57

Index.

109

Fermentation, butyric, 28, 29

lactic, 87

of beer, 59, 6 1, 62

of cellulose, 29

of milk, 92

of starch, 10

of tomatoes, 62

of urine, 9

of wine, 60, 6l, 62

Fire-blight, IO

Gattine, 14
Glanders, 106
Glaucothrix, 75
Gliothrix, 75
Gonorrhoea, 105

Hamatococcus, 76
Hog-cholera, 13
Hormiscium

album, Bonord. , 63

cerevisice, Bail, 59

cerevisice, Bonord. , 64

z>z'«z, Bonord., 64

Hygrocrocis Vandelli, Men., 36
Hypheothrix Kiihniana, Rab., 55

Kephir, 92

Lactic fermentation, 87
Leprosy, 32, 106
Leptonema niveum, Rab., 37
Leptothrix, 34, 75
— — buccalis, Rob. , 34, 94

gigantea, Mill., 93

Kiihniana, Rab., 55

Lanugo, Kiitz. , 35

ochracea, Kiitz., 73

Leptothrix parasitica, Kiitz. , 35, 73

pusilla, Rab., 35

subtilissima, Rab. , 90

tenuissima, Rab., 90

Leuconostoc, 16, 75

mesenterioides, Van T., 16

M

Malaria, 89, 106
Measles, 13, 105
Melanellaj/lexuosa, Bory, 47

Spirillum, Bory, 50

Merismopedia

Goodsirii, Hus., 20

hyalina, Kiitz. , 22

litoralis, Rab., 21

urintz, Rab., 21

ventriculi, Rob. , 20

violacea, Kiitz., 22

Merismopedium

chondroideum, Wittr., 22

Reitenbachii, Casp., 21

Microbacteria, 69, 106
Micrococcus, 6, 13, 95

amylivorus, Burr., 10

aurantiacus, Cohn, 8

black, 95

bombycis, Cohn, 12

candidus, Cohn, 10

chlorinus, C0/z«, 8

Crepusculum, Cohn, 10

cyaneus, Cohn, 9

diphtheriticus, Cohn, 1 1

• fulvus, Cohn, 8

gallicidus, Burr., 13

griseus, Wint., 14

insectorum, Burr., 13

luteus, CM», 8

ovatus, Wint., 14

— prodigiosus, Cohn, ^

septicus, Cohn, 12

suis, Burr., 13

toxicatus, Burr., 15

urese, Cohn, 9

vaccinse, C0/fc», 1 1

violaceus, Cohn, 9

Microhaloa rosea, Kiitz., 17
Micro-millimetre, 101

no

Index.

Microsphara vaccina, Cohn, 1 1
Microsporon septicum, Klebs, 12
Microzyma bombycis, Bech., 12
Molluscum, 89
Monads, 2, 98
Monas, 98

Crepusculum, Ehr., to

erubescens, Ehr. , 86, 99

fallax. Warm., 100

gracilis, Warm., 86, 99

Mulleri, Warm. , 99

Okenii, Ehr., 20, 85, 98

prodigiosa, Ehr., 7

Termo, Mull., 23

vinosa, Ehr., 86, 98

Warmingii, Cohn, 86, 99

Monostroma rosea, Curr., 1 8
Mucor-ferment, 67
Mucorini, 76
Mucor Mucedo, Linn. , 80

racemosus, Fres., 67

Mycoderma

— — cerevisiiz, Desm., 64

vim, Desm., 64

Myconostoc, 41

gregarium, Cohn, 42

Mycoprotein, 74

Nosema bombycis, Nag. ,
Nudo-flagellata, 99

O

OEdema, malignant, 91, 106
Oidium albicans, Rob., 65
Ophidomonas, 46

Jenensis, Ehr., 53

sanguinea, Ehr., 51, 53

Oscillaria

alba, Vauch., 36

arachnoidea, Ag. , 38

leptomitiformis, Men. , 38

tigrina, Rom., 39

versatilis, Kiitz. , 38

Palmella infusionum, Ehr., 23

mirifica, Rab., 8

prodigiosa, Mont., 7

Palmellina flocculosa, Radl., 55
Panhistophyton ovatum, Leo., 14
Pathogenous species, 5
Pebrine, 14
Penirillium, 77, 80
Phragmidiothrix, 75, 92

multiseptata, Eng. , 93

Phthisis, 32, 1 06
Phycochromacege, I, 34
Pleomorphy, 76, 80
Pleurococcus roseo-persicinus,

Rab., 17

Pneumo-enteritis of pig, 91
Pneumonia, 105
Polybacteria

catenata, Van T., 96

sulfurea, Van T. , 96

Protean species, 78, 83
Protococcus roseo-persicinus, Kiitz. ,

J7
Punctula

cubica, Van T., 96

glomerata, Van T., 97

rosea, Van T. , 96

Pus, blue, 26
Pustula maligna, 31
Putrefaction, 10, 23
Pyaemia, 12, 105
Pyorrhrea, 94

Recurrent fever, 44, 106

Rhabdomonas

rosea, Cohn, 86, 100

Saccharomyces, 58

albicans, Reess, 65

apiculatus, Reess, 62

cerevisise, Mey., 58, 67

Index. 1 1 1

Saccharomyces conglomerate,

Spirillum volutans, Ehr., 50

Reess, 60

— — robustum, Warm., 51

— — coprogenus, S. et S., 66
— — ellipsoideus, Reess, 60

Spirobacteria, 70, 106
Spirochaeta, 43

exiguus, Reess, 61

Cohnii, Wint., 44

formation of spores, 57
glutinis, Cohn, 63

gigantea, Warm., 45
Obermeieri, Cohn, 43

guttulatus, Wint., 66

plicatilis, Ehr., 43

— minor, Eng., 59

Spirochcete

Mycoderma, Reess, 64

denticola, Arn. , 44

olei, Van T., 67

dentium, Mill., 44

Pastorianus, Reess, 6 1

Spiromonas, 45

sphaericus, Sacc., 62

Cohnii, Warm., 46

Saccharomycetes, 57, 79

volubilis, Perty, 45

Sarcina, 20, 95

Spirulina,43, 94

hyalina, Wint., 22

alba, Van T., 94

litoralis, Wint., 21

plicalilis, Cohn, 43

Reitenbachii, Wint., 21

tenuissima, Kiitz., 94

rents, Hepworth, 22

Splenic fever, 31, 106

— solani, R. et B., 95

Spores, germination of, 3, 17, 28

urinae, Welck., 21
— — ventriculi, Good., 20

reproduction by, 3, 57, 74
Sporonema gracile, Perty, 90

Scarlet fever, 13, 105

Staining fluids, 103

Schizomycetes, I, 68

Starch, fermentation of, 10

Schizophyceae, 76

in fungi, 29, 50

Schizophytae, I, 70
Schlaffsucht, 12

Streptococcus, 70
Streptothrix, 40

Scrofula, 106

Forsteti, Cohn, 41

Septicaemia, 12, 105, 106
Silkworm disease, 12, 14

Symphyothrix nivea, Briig., 38
Syphilis, 13, 91, 106

Small-pox, n, 105

Sphaerobacteria, 69, 105

Sphaerotilus, 53

natans, Ktitz., 53, 56

T

ochraceus, Breb., 54

Spirillum, 46, 94

Teeth, decay of, 35, 44, 47, 94,

amyliferum, Van T. , 50

1 06

attenuatum, Warm., 52

Thrush, 66

— Jenense, Wint., 53

Torula, 32, 67, 73

plicatile, Duj., 43
rosaceum, Klein, 94

cerevisice, Turp., 58
Tuberculosis, 32, 106

Rosenbergii, Warm., 52

Typhoid, 106

— rufum, Perty, 94

Typhus, 13, 105

Rugula, Wint. , 47

sanguineum, Cohn, 51,94

serpens, Wint., 47

U

tenue, Ehr., 43, 48

Undula, Ehr., 42, 49, 94

Unit of measurement, 7, 101

litorale, Warm., 49

Urine, 9, 21, 91

violaceum, Warm., 52

Ustilagineae, 80

112

Index.

Variola, n, 105
Vibrio, 46, 69

cyanogenus, Fuchs, 26

— Lineola, Miill. , 24

prolifer, Ehr., 49

Rugula, Miill. , 47

serpens, Miill. , 47

Spirillum, Miill., 50

subtilis, Ehr. , 27

syncyanus, Ehr., 26

synxanthus, Ehr., 25

tremulans, Ehr. , 24

C/^wAz, Miill., 49

xanthogenus, Fuchs, 25

Vibrion butyrique, 29

Vinegar, formation of, 65, 85, 106

Volvox punctum, Miill., 99

W.

Woolsorters' disease, 31

Yeast, 59, 60

Yeast Fungi (see Saccharomy-

cetes)

Yellow fever, 95
Yellow milk, 25

Zoogalactina imetropha, Sette, 7
Zooglcea, 3

Zooglcea Termo, Cohn, 23
Zymogenous species, 5

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