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1 Stower, K. M. f. A., March and April, 1907, xlv. 1.

2 On this subject Tschirkowsky contributes an important article in A. f. 0., Ixviii.,
i., 1908.

3 See the chapter on ' Conjunctivitis.'


bacillus alone ; in many cases it is due to the Stapliylococcus or other

Corneal infections from the influenza bacillus are described by Zur
Nedden and A. Knapp.

De Berardinis reports having cultivated Strept&thricete from super-
ficial corneal ulcers ; in one case there were several varieties. Inocula-
tion experiments with the same organisms also produced superficial
ulcerations. 1


ADDARIO, Keratite fasc. Arch, di Ottalm., 1904, XII, p. 1.

AREXS, Keratites suppuratives. Arch. med. beiges, October, 1904.

AXENFELD, Serumtherapie in inf., August, 1905. Further, see UHTHOFF and


BACH and NEUMANN, Die eitrige Keratitis beim Menschen. A. f. A., 1897, Bd. 34.
BASSO, Internat. Kongr. in Kom, 1894, ferner Cheratite ipopion da bacillus mucosus

ozaenae. La clinica ocul., 1903, p. 1479.

BARGETOX, Un cas de botryomycose de la cornee. Lyon, 1905.
BENEDETTI, La clinica ocul., 1906, VII, S. 2690.
BIETTI, II bacillo piocianico nel cherato ipopion. Ann. d'ottalm., 1898, vol. 27,

p. 578, also ibidem, 1905, XXXIV, 11.
BROSE, Ulc. corn. serp. The Ophth. Bee., 1904, p. 55.
DE BERARDINIS, Ulcera corn, da bact. coli. Ann. di Ottalm., 1904, XXXIII, p. 18.

Ibid., Ulc. corn, da streptothrix. -Ibid., pp. 385 and 914.
BUTLER, T. H., Clinical Features, etc., of Acute Ophthalmia. E. L.O.H. Bep.,

XVII, i., p. 115.

CALDERARO, Clinica oculist., August, 1903.
COLLOMB, Arch, d'ophth., 1903, S. 129.

COLOMBO and BICCHI, Ann. di Ottalm., 1904, XXXIII, p. 865.
COPPEZ, H., Des alterations corneennes dans la diphth. de 1'oeil. Bev. gen. d'opht.,

1895, p. 177. Ibid., Journ. med. de Bruxelles, August 31, 1899, Nr. 35.
CUENOD, Bacteriologie et Parasitologie clinique des paupieres. These de Paris,

1894. Ibid., Du pneumocoque en pathologic oculaire. Congres de la Societe

francaise d'ophthalmologie, May 6-9, 1895, t. 5.
DINKLER, Zwei Fiille von Ulcus perforans corneae nach conjunct! val-Tripper.

(Tripperkokken im Gewebe). A. f. 0., 1888, Bd. 34, 3, S. 5.
DOETSCH, Anatomische und bakteriologische Untersuchungen uber infantile Xerosis

und Keratomalacie, sowie Bemerkungen iiber die Verhornung des Binde-

hautund Hornhautepithels. A. f. O., Bd. 49, 2, S. 405, and Ophth. Klinik.,

1900, Nr. 18/19.

ERDMANN, Diplobazillen-Keratitis (cf. ' Diplobacillary conjunctivitis ').
FUCHS, Keratomykosis aspergillina. Wiener klin. Wochenschr., 1892, Nr. 17.

Ibid., Bingabszess d. Cornea. A. f. O., 1903.
GASPARRINI, II diplocoeco di Frankel in pathologia oculare. Ann. d'oftalm., 1893,

vol. 22.
GNAITE, Le diplocoque de Fraenkel en pathologie oculaire. Internat. Congress in

Koine, 1894.
GOURFEIN, Bevue Med. de la Suisse Bomande, 1902, Nr. 2. Ibid., Bac. subtilis,

X. Congres Intern. Luzern.

1 There is also a recent record by Zur Xedden, who found an aerobic Streptothrix in a
case of keratitis disciformis, which went on to suppuration.


HANKE, Zeitschr. f. Augenh., 1903, II, Kingabszess. Ibid., Zeitschr. X, 1903,

S. 373, K. M. f. A., 1905, I, S. 724, and Wiener klin. Rundschau, 1906,

Nr. 26. Ibid., Proteus-infection. Ophth. Ges. Wien, April 17, 1907.
HERBERT, Keratitis punctata (Bombay). Ophth. Review, 1901, p. 335.
HERTEL, E., Uber eitrige Keratitis beim Menscheu. A. f. O., 1901, Bd. 53, 2.
HIPPEL, E. v., Das Geschwiir der Hornhauthinterflache (Ulcus internum cornese).

Sep. -A. aus der Festschrift zur Feier des 25jahrigeii Professoren-Jubilk'ums

von Geheimrat v. Hippel in Halle, 1899.
HOLDEN, Examen clinique et anatomique d'un ulcere serpigineux de la cornee cause

par le pneumocoque. Ann. d'ocul., 1898, 119, p. 463.
HORI, Zur Anatomie einer Ophthalmia hepatica. A. f. A., Bd. 31, S. 393, and

Heidelberger Kongress, 1895.

HOTTA, Infektion der Cornea durch Speichel. K. M. f. A., 1905, XLIII, II, S. 237.
KALT, Ulceration corneenne dans 1'ophthalmie purulente. Mode de propagation

des microbes. Societe de biologie, December 7, 1895.
KNAEBEL, Keratomalacie. Inaug. Dissert., Tiibingen, 1901.
KIPP, Hypopyon ulcer. Arner. journ. of ophth., November, 1904.
KOUN, De la Keratomalacie. These de Bordeaux, 1903.
KRUGER, Z. f. A., 1903, IX, S. 192.
LEBER, Keratomykosis aspergillina als Ursache von Hypopyon-Keratitis. A. f. 0.,

Bd. 25, 2, S. 285. Die Entstehung der Entztindung. Leipzig, 1893.
LUNDSGAARD, Ein Fall von Hypopyon - Keratitis mit Reinkultur von Hefe.

K. M. f. A., January, 1900.

McKEE, Ulc. of Cornea from M.-Ax. Diplobacillus. Ophth. Record, 1907.
McNABB, H. HORSMANN, Bact. Exam, of Twenty-five Cases of Serpent Ulcer of

the Cornea with Hypopyon. Ophth. Review, 1906, p. 67.
MACNAB, A., Klin. Monatsbl., XLII, 1904, 1, S. 54. Ibid., Uber Infektion der

Cornea durch den Bacillus pyocyaneus. K. M. f. A., 1904, XLII, Bd. 1,

S. 65. Ibid., Ulceration of the Cornea. London (Bailliere, Tindall and

Cox), 1907.
MORALES, A., Ulceras infectiosas de la Cornea. Arch, do oft. Hist. Amer., 1907,

VII, p. 147.
MORAX, La Conjonctivite subaigue, etude clinique et bacteriologique. Ann. d'ocu-

listique, 1897, t. 124, p. 5. Ibid., Ann. d'ocul., 1904, CXXXII, p. 409.
MORAX et PETIT, Considerations cliniques et bacteriologiques sur les inflammations

aigues de la conjonctive. Annales d'oculist., 1898.
OLLENDORF, A. f. 0., 1900, Bd. 49, S. 455.
PAINBLAN, Contribution a 1'etude du role du pneumocoque en pathologic oculaire.

These de Lille, 1897.
PANAS, Arch, d'opht., 1902, XXII, p. 157.
PAUL, K. M. f. A., 1905, XLIII, I, S. 54 and 154.
PATERSON, Notes on the Bacteriological Investigation of Thirty Cases of Hypopyon

Ulcer of the Cornea. The Scot. Med. and Surg. Journ., 1904, S. 505.
PETIT, P., Sur une forme particuliere d'infection corneenne a type serpigineux.

Annales d'oculist., 1899, p. 166. Ibid., Recherches cliniques et bacterio-
logiques sur les infections aigues de la cornee Paris, Steinheil ed., 1900.
ROCHAT, Diplobazillen bei Ulc. serp. Nederl. Tijdschrift v. Geneeskunde, 1904,

S. 718. (K. M. f. A., 1905, I, S. 524.)
ROMER, Experimentelle Grundlagen fur klinische Versuche einer Serunitherapie des

Ulcus corneae serpens nach Untersuchungen iiber Pneumokokkenininiunitat.

A. f. O., 1902, Bd. 54, 1.

SALVANESCHI, Annali di Ottalmol., XXXV, 1906.
SCHIRMER, Ein Fall von Schimmelpilzkeratitis. A. f. O., 1896, Bd. 42, 1.


SCHIMMELPFEXXIG, W., Uber einen Fall von infantiler Conjunctivalxerose mit

Keratomalacie. A. f. O., 1897, Bd. 43, 1, S. 41.
SCHMIDT, Arch. f. Augenh., 1902, XLV, S. 79.
SCHUMWAY, Sect, of Ophth. Philadelphia, 1906, Ap.
DE SCHWEINITZ. G. E., "Wound of the eyeball. Mikroorganisms. 46. Amer. med.

Assoc. Baltimore. Ophth. Review, p. 32, and Ann. d'ocul., 1899, T. 121,

p. 136.

SECONDI, Sul cherato-ipopion. Clinica moderna, 1895, 1.
SMITH, D., Arch, of Ophth., 1905 and 1906, 34 and 35.
STOEWER, Ein Beitrag zur Atiologie der Keratitis. XII. Congres intern. Section IX.

ophth., p. 29. Uber die Wirkung pathogener Hefen am Kaninchenauge.

A. f. O., Bd. 48, 1, S. 178. K. M. f. A., 1905, XLIII, II, S. 142.
SZCZBALSKI, Pyocyaneus. A. f. A., 1905, LI, S. 249.
UHTHOFF, Beitrage zur pathologischen Anatomic des Auges. Partielle Nekrose der

menschlichen Hornhaut durch Einwanderung von Schimnielpilzen. A. f. O.,

1881-1883, Bd. 29, 3, S. 178.
UHTHOFF and AXEXFELD, Bakteriologische Untersuchungen bei eitriger Keratitis,

besonders deni Ulc. serp. Naturforscherversamrnlung in Wien, 1894. Ibid.,

Eitrige Keratitis des Menschen. Vortrag des ersteren auf dem Heidelberger

Kongress, 1895, der Naturforscherversammlung in Llibeck. Berliner klin.

"Woch., 1895. Ibid., Beitrage zur pathol. Anatomie und Bakteriologie der

eitrigen Keratitis des Menschen. A. f. O., 1896, Bd. 42, 1 (cf. here older

Literature). Ibid., Weitere Beitrage zur Bakteriologie der Keratitis des

Menschen. A. f. O., 1897, Bd. 44.
VALLAUDE, These de Bordeaux, 1901, S. 78.
VELHAGEN, Miinch. med. Woch., 1901.
Vossius, Statistik des Trachoms. Sep. -A. aus den Arbeiten des in Budapest, 1894,

abgehaltenen VIII. internat. Kongr. f. Hyg. u. Dermographie, 1897.
WIDMARK, Quelques etudes de bacteriologie ophthalrnique. Archives d'ophth.

July, 1889.
ZUR NEDDEN, Seltene Infektionskrankheiten der Hornhaut. K. M. f. A., June,

1906, Bd. l.lbid., A. f. A., 1905, 52, S. U3Ibid., A. f. 0., 1907, XLV,

p. 267.

Amongst the infectious forms of keratitis, the infection with the
mould fungi ' keratomycosis ' merits a consideration quite apart. 1

Leber's excellent researches have shown that when a rabbit's cornea
is infected with the spores of the Aspergillusfumigatus, a necrosis occurs
around the site of inoculation, and at its periphery a dense infiltration
ring is formed. The necrotic mass of tissue riddled with the mould is
then cast off in toto, like a sequestrum.

Those observers who have recorded cases in human beings (Leber,
Fuchs, Uhthoff, Axenfeld, Schirmer, Markow, Basso, Collomb, Gen-
tili, Ball, Wicherkiewicz, Kayser, Ellet, Johnson, Buchanan, Oster-
roth, Martin, Zade) agree that the strange-looking, dry, slightly
prominent, diseased area is separated from the surrounding tissue by
a demarcation ring, and is slowly cast off. (In the differential diag-
nosis it should be noted that Martin, in the A. f. A., 1905, li., p. 141,

1 Literature: see Kayser, A'. J/. /. A., 1903, xli., Bd. i., and Johnson, ibid., Bd. 2.


found a grain husk adherent to the cornea, and enclosed in a bac-
terial mass consisting of the Bacillus xerosis. De Bono, in the Ann.
di OttaL, 1905, xxxiv., p. 946, found the Mucor mucedo in a ' pseudo-
membrane ' covering the cornea and only loosely adherent to it,
which healed without leaving any trace.) In the sequestrum which
is permeated with the mycelium the corneal lamellae are completely

In most cases reproductive organs were not seen in the cornea ; in
Ball's case alone was there any hint of the presence of Aspergillus.
Recently Zade has reported the occurrence of fructification organs in
two cases on the surface of particles taken from the centre of the
affected area. The cases were characterized by their special chron-
icity, and the absence of any sequestrum formation. Eight animals
were inoculated with this Aspergillus, and in two of the cases Zade
found the fructification organs in the centre of the cornea. He states
that they could only be obtained with fresh material, and after con-
servation they readily disappeared. They first appeared at a late
stage, about the sixth day, and even then only on the surface and in
the centre.

As a rule, the infection is due to earth or some vegetable substance.
In the single cases recorded by Uhthoff and Axenfeld, B. Kayser, and
Johnson, the foreign body was still visible in the sequestrum. I have
shown on other occasions, and would again note here, that there is a
mild form of keratomycosis, which when only superficially observed
appears like a dense infiltrate or a keratitis fasciculosa (see Fig. 68).
The three cases last mentioned were considered as such a keratitis,
but on closer examination I was able to demonstrate a peculiar small,
delimited nodule, in which the suspected mould was found. Martin
recorded a similar case.

Cultures made with every precaution showed that these cases were
due to Aspergillus fumigatus.

The Aspergillus fumigatus has the following characteristics : Besides
growing on the ordinary media, they will grow well on acid substances
(potatoes, bread-infusion, yeast). The young colonies are soft white ;
when the mycelium forms, the centre becomes greenish, then greenish-
grey, and finally the whole culture is smoky-grey, from the formation
of large numbers of spores.

The varieties of Aspergillus are characterized by variations in the
spore-bearing organ. This rises out of the mycelium, and ends in a
knob bearing the radially-arranged ' sterigmen,' from which the spores
(conidia) bud off (cf. Fig. 62). The best method of examining speci-



mens is in hanging-drop, or in some glycerine in which particles
taken from the cornea have been squeezed out. The preparation

should not be stained. In sec-
tions the mould is best stained
by the Gram-Weigert method.
The aniline dyes are not so



Reproductive organs with the stengmata ; (FREIBURG CASE).

comma fallen on.

Vegetable foreign body with mycelium. Case from the Freiburg clinic (c/. Kayser).

good (the basufones being worst, especially the commonly-used Loffler's
methylene blue).

1 From Plaut, 'Kolle-Wassermann Handbook,' 1903, vol. i., p. 559.



The record by Ellet is inexact. He takes no account of the previous
literature, and without any particulars speaks of Aapergtilut nigcr.
Penicillium glaucum is recorded in Wicherkiewicz's case, but it must
be considered as doubtful if this mould was really present, as it has
never been described as pathogenic. No particulars were given con-
cerning its morphology and cultures, and experiments on animals
were not carried out.

From a white, prominent, partly delimited corneal infiltrate Baquis
cultivated a peculiar Hypliomyccte, whose identification was not pos-

Vegetable foreign body with mycelium.

sible, as no spore formation was obtained (Oospora ascoform ? Verti-
cillium rubrum ?).

Halbertsma also found that the Aspergillus flavescens was patho-
genic for the cornea of the rabbit. Aspergillus nigcr, A. ficuum,
A. u-entii, and to a very slight extent the A. candidus, have been
described as having a moderate degree of pathogenicity for the cornea
of the rabbit, and to a certain extent also for the vitreous and the
choroid. A. glaucus, ostianus, minimus, clavatus, varians, and novus,
on the other hand, were found to be quite inactive. Buchanan states
that many strains of Aspergillus and Penicillium are capable of patho-
genic activity.

The relative rarity of keratomycosis, in proportion to the frequency


of the Aspergillus, is explained by the fact that it will only develop in
the cornea when it is directly planted into its tissue by a foreign body,
or is rubbed into it ; otherwise it can only produce a corneal lesion
with difficulty.

Best 1 records an interesting case of this variety in both eyes of a
young blackbird. In the vitreous, the retina, the choroid, the anterior
chamber, and the bone of the sclera, there was a dense felt-work of a
mould. No cultures were available. Best considered that an injury,
perhaps by pecking, was the cause. He recalled the fact that a general
experimental infection of the blood with the spores of Aspergillus will
readily cause a metastatic infection of the eye.

In man, too, similar infections of the vitreous by moulds have been
described by Leber and Nobbe, Eomer, and Kampherstein. 2 In these
cases there was a necrosis in the immediate vicinity of the mycelium,
and around that a suppuration. Leber and Nobbe, as well as Rollet
and Aurand, have produced the same result by experimental infection
of the vitreous. In the vitreous no reproductive organs were formed.
In a phthisical eye Schirmer has demonstrated microscopically the
presence of a mould infection passing from the cornea into the

Koellner, in Michel's clinic, described a mould infection of the
sclera with partial necrosis. Here, too, there was a sequestrum
formed. The nature of the mould could not be determined by


The literature up to, and including, 1903 is given by Kayser and by Johnson in
the K. M. f. A., 1903, XLI, I, p. 50, and XLI, II, p. 206.

BAQUIS, Una nuova forma di cheratomicosi. Annali di Ottalmol., 1905, XXXIV,

p. 945.

BUCHANAN, Mycosis of the eyeball. Glasgow Med. Journ., December, 1905.
KAMPHERSTEIN, K. M. f. A., 1903, XLI, I, S. 151 (here is the literature of mould

infections of the vitreous).

KOELLNER, Schimnielpilzinfektion der Sklera. Z. f. A., 1906, XLI, S. 441.
MARTIN, A. f. A., 1904, L, S. 177.
OSTERROTH, Berl. klin. Woch., 1905, Nr. 7.
ROLLET et AURAND, Experiment. Aspergilluskeratitiden. Revue generale d'ophth.,

July, 1906 (K. M. f. A., 1905, I, S. 774), and Rev. gener., 1907, S. 1.
ROSENSTEIN, Ein schimmliges Geschwtir der Lidhaut. Zentralbl. f. A., January,

ZADE, A. f. O., 1907, LXV, p. 41, etc.

1 Deutsche Med. Wpch., 1905, S. 1821.

2 Aspergillus fumigatus occurred in Leber-Nobbe and Homer's cases; in Kampherstein's
case the organism was doubtful.


Under the name of ' botryomyeosis ' Bargerton described a tumour-
like vascular growth in the cornea. It had a broad base and a nodular
surface, and developed after an injury to the cornea. Microscopi-
cally it consisted of vascular granulation tissue. Dor and Bargerton
considered the changes to be identical with the botryomyeosis of the
skin described in man (which affects the face and the hands, two cases
being recorded in the eyebrows) . In these cases a fleshy fungoid granula-
tion tissue tumour formed a few weeks after an injury (like the growth
in horses after castration) ; on removal it rapidly healed, and did not
recur. The condition was considered by Poncet and Dor not to be
due to the Botryococcus equi, but to a special Botryococcits, 1 an
organism which resembled the Stapliylococcus pyogenes aureus in
almost every point, and by many is considered to be identical with it.
The chief difference, according to Poncet and Dor, is that their coccus,
unlike the Staphylococcus, does not form pus, but causes an exudation
of lymphocytes. The bouillon culture remains clear (in contrast to
the Staphylococcus) ; an orange-yellow mass forms at the bottom.
On solid media a thick orange-yellow and slightly wrinkled slime
forms, which when examined shows Gram-positive cocci, resembling
a typical Sarcinee. In the later stages of botryomyeosis of the skin
hyaline bodies ' grains muriformes ' should form. (In the granula-
tion tissue in the cornea neither such granules nor the Boti-yococci
have been demonstrated. There is no proof that these cases were
anything different from what has been described in the literature as
' granulomata.')

Dor and Bargerton consider their case as identical with the one
described by Schirmer and Reishaus (Beitr. Zeit., August 31, 1899)
as a ' fibroma of the cornea,' in which these authors found appear-
ances which they, with Busse, considered to be saccharomyces

Further investigation is necessary to determine the pathogeneais of
these and other corneal growths.

The literature is found in a paper by J. Bargerton, ' Un Gas de
Botryomycose de la Cornee,' These de Lyon, 1905, and Ten Sietoff,
Weekblad, 1899.

A rare condition is reported by Lundsgaard (K. M. f. A., 1900,
xxxviii., p. 13), Stower (Inter. Med. Congr., Moscow, 1897, vi., p. 29,
and A. f. 0., 1898, xlviii., p. 178), G. F. Keiper and Severance
Burrage (Amer. Med. Ass., 1907, Atlantic City, Ophth. Sec., p. 87), as
due to Hefse.

1 Identical with the Micrococcus asciformis (Johne).


Lundsgaard's case was one of atypical hypopyon - keratitis of
moderate severity ; the others were severe non - purulent ulcers.
Lundsgaard and Stower found Hcfa rosa in pure culture. The
American authors did not succeed in an exact identification, as their
organism was mixed with Sarcince, bacilli, and Diplobacilli.

This Hcfa (Lundsgaard) at first grew at brood temperature, and,
just as in Stower's experiments, produced nodules in the iris, from
which weeks later the Hefa could again be grown. In the vitreous a
white membrane was formed. In the cornea of a rabbit a benign
rapidly healing inflammation occurred without a hypopyon. After
continued cultivation the optimum temperature sank, and in this
particular the strain which Lundsgaard grew took on the charac-
teristics of the common non-pathogenic Hcfa rosa.

These findings remain isolated, 1 so that there can be no great import-
ance ascribed to the Hcfa in the etiology of corneal inflammations.
The authors quoted consider that HeUe were very probably the cause
of the condition present in their cases.

Klein has obtained a nodular inflammation of the conjunctiva and iris
through endogenous channels ; and Stock carried out in my laboratory
a full experimental and microscopic research into the nature of these
peculiar haematogenous inflammations (cf. Ophth. Congr. Heidel.,
1907, and Ziegler's Bcitmgc z. Path. Anat., 1908).

ZUP Nedden's Bacillus of Marginal Uleeration.
(Cf. PLATE III., FIG. IT'.) 2

Superficial corneal ulcers, marginal in position, develop by the
breaking down of infiltrates ; these may be single, or multiple when
they tend by their confluence to the formation of trough-shaped
ulcers. In the floor of such marginal ulcers, and more rarely in
centrally - placed processes, Zur Nedden 3 found a bacillus which
differed from any known organism. From its frequent occurrence,
and its pathogenicity for the cornea of rabbits, he rightly considered
it to be the cause of these ulcers.

The bacillus has been found in the same hospital in a case of neuro-

1 In the sections of a so-called fibroma of the cornea, stained with Busse's Hefa-st&in,
Schiruier found fuchsinophile granules -which presented the appearance of Hefcc (Beit. c.
Aug., 1899, xxxi.). This peculiar finding is analogous to that in the chronic granulation
tissue tumours which can be produced by the action of the pathogenic Hefce.

2 The drawing is from a direct preparation from an ulcer ; the preparation was sent me
by Dr. Zur Nedden.

3 A.f. 0. 1904, Bd. lix., S. 360 ; also K. M. f. A., 1906, xliv., Bd. i., S. 479.




paralytic keratitis, 1 and in London by Macnab. 2 A clinical point of
great interest is that the bacillus has only been found in cases of
inflammation of the cornea. In such cases they can be found in the


conjunctival sac, from whence they have passed into the cornea. In
a pure conjunctivitis they have not yet been found.

The clinical appearance is so far typical in that the Zur Nedden's
bacillus alone has been found
in any quantity in these con-
ditions, provided that they are
not incidental in the progress



AGAR CULTURE, x 1,000.


Large superficial and small deep colonies.

of other conjunctival infections (Koch- Weeks, diplobacillary, pneumo-
coccal, or staphylococcal) .

1 Haupt, Inaug. Dissert., Bonn, 1902. Here are also given the full bacterial findings in
this affection.

2 'Ulceration of the Cornea,' London, 1907.


Morphology. Rods, either straight or slightly curved, lying very
often in pairs ; individuals are 0'7 /* long, and 0'6 fj. broad. Smaller
individuals and filaments are rare. Their ends are rounded. Clearer
areas (vacuoles) can be seen at their ends, and sometimes also at
their centres, when they are faintly stained. In many features the
bacilli resemble xerose bacilli. Gram negative. No chain or capsule

Cultures The colonies on agar are 2 to 7 millimetres in diameter
after twenty-four hours, and by transmitted light appear bluish and
translucent ; they are slightly raised, with round and sharp margins.
They tend to run together, and form a thick mucous slime. When
the medium is poured out in Petri dishes or plates, small round or
whetstone-shaped colonies develop in the substance ; on the surface,
however, they are large, round, and have a small dark central area.
In transmitted light they are concentrically marked. In the deep
layers of the agar they do not grow at all ; they are obligate aerobes.

Colonies on gelatine plates are transparent, bluish, and homo-
geneous. In gelatine stab culture growth takes place only in the upper
part, with the formation of a flat nailhead.

In sugar-agar there is no formation of gas, but the medium becomes

Cow's milk is coagulated.

In bouillon slight growth, without indol formation.

On potatoes a thick, yellowish-brown growth.

On human blood-serum or Loffler's serum a thick greyish-white

No motility.

The temperature optimum is that of the body ; still, there is a
scanty growth at 10 and 40 C. After three-quarters of an hour

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