IN SUSCEPTIBLE ANIMALS. 525 
of other mice which have died as a result of infection. House mice are also 
susceptible. Rabbits, guinea pigs, pigeons, and chickens were found by 
Léffler not to be susceptible to infection by feeding. 
BACILLUS OF CAZAL AND VAILLARD. 
Obtained by Cazal and Vaillard (1891) from cheesy nodules upon the 
peritoneum and in the pancreas of an individual who died in the hospital 
at Val de Grace. 
Morphology.—Bacilli with rounded ends, but little longer than they are 
broad; solitary, in pairs, or in chains of ten to fifteen or more elements. 
Stains with the usual aniline colors, but not by Gram’s method; the 
extremities of the rods are more deeply stained than the central portion— 
‘‘ polar staining.” 
Biological Characters.—An aérobic and facultative anaérobic, liquefy- 
ing, motile bacillus. Doesnotform spores. Grows in the usual culture media 
at the room temperature—more rapidly in the incubating oven at 37° C. In 
gelatin stab cultures, at the end of twenty-four nours, a series of puncti- 
form, white colonies is developed along the line of puncture; upon the sur- 
face development is more abundant, and at the end of forty-eight hours 
liquefaction commences ; this progresses slowly from above downward, 
and a white, flocculent deposit accumulates at the bottom of the liquefied 
eee Upon the surface of agar, at the end of twenty-four hours at 37° 
-, &@ moist, transparent, opalescent layer is developed, which rapidly ex- 
tends over the entire surface ; later this layer becomes somewhat thicker, 
whitish, and cream-like in consistence, without losing its transparency. 
Upon potato a thick, prominent, moist, and slightly viscid layer is devel- 
oped, which at first has a pale-yellow and later a yellowish-brown color. 
In bouillon development is abundant, producing a milky opacity of the 
liquid; a thick, flocculent deposit accumulates at the bottom of the tube ; 
the reaction of the culture liquid becomes very alkaline. All of the cultures 
give off a peculiar odor, slightly ammoniacal and resembling that of putrid 
urine. The cultures retain their vitality for several months—in a closed 
tube for more than a year. The thermal death-point is 60° C. with fifteen 
minutes’ exposure. 
Pathogenesis.—Pathogenic for rabbits and mice, but not for guinea-pigs. 
In mice death occurs from general infection, at the end of forty-eight to 
sixty hours, from the subcutaneous injection of one eighth cubic centimetre 
of a recent bouillon culture. In rabbits injection of one cubic centimetre 
into the circulation causes the death of the animal in thirty-six to fifty 
hours. The symptoms induced are a foetid diarrhcea and paralysis of the 
extremities. When smaller doses are injected (0.5 cubic centimetre) a 
chronic malady is developed, characterized at the outset by diarrhcea and 
emaciation, then by the development of tumors which resemble those found 
in the man from whom the cultures were first obtained. These tumors are 
for the most part located in the subcutaneous connective tissue; after a time 
they attain the size of a chestnut and ulcerate, allowing the escape of a 
semi-fluid, purulent material. The animalsusually recover. Similar tumors 
are developed as a result of subcutaneous injections of one to three cubic 
centimetres of a recent bouillon culture. 
BACILLUS OF BABES AND OPRESCU. 
Obtained by Babes and Oprescu (1891) from a case of septiceemia hamor- 
rhagica presenting some resemblance to exanthematic typhus. 
Morphology.— In agar cultures the bacilli are from 0.4 to 0.5 # thick, and 
are frequently united in pairs; associated with these rod-shaped bacteria are 
forms which are of a short oval. In gelatin cultures oval forms are more 
numerous ; they have a diameter of 0.3 to 0.4 uw, and often appear to be 
surrounded by a capsule. In fresh cultures the bacilli are often in form of 
