IN SUSCEPTIBLE ANIMALS. 521 



room temperature better in the incubating- oven. Upon gelatin plates, at 

 20 C., at the end of twenty-four hours small, angular, transparent scales 

 may bo seen upon the surface with a low-power lens; at the end of three or 

 four days these form flat, more or less irregular, shining, gray colonies, with 

 thin and of ten dentate margins ; these colonies may become confluent and 

 form a dry, scaly layer which by reflected light has a peculiar, fatty lustre 

 In gelatin stab cultures the superficial growth is in the form of a trans- 

 parent, dry, grayish layer with dentate margins, not more than three to five 

 millimetres in diameter. Upon agar, at 36 to 37 C., a thin, whitish-gray, 

 dry layer is formed. 



Pathogenesis. Pathogenic for mice, for guinea-pigs, for linnets, and for 

 green-finches; less so for sparrows. Chickens, pigeons, and rabbits, accord- 

 ing to Klein, are immune. Of eight mice inoculated subcutaneously with 

 one or two drops of a bouillon culture, six died within forty-eight hours 

 and two recovered. Out of eight guinea-pigs inoculated in the same way 

 four died in forty-eight hours and two recovered. At the autopsy the 

 lungs and liver were found to be hyperaemic, the spleen not enlarged. The 

 bacilli were present in large numbers in blood from the heart and in the 

 lungs. 



BACILLUS GALLINARUM. 



Obtained by Klein (1889) from the blood of chickens which succumbed 

 to an epidemic disease resembling " fowl cholera." The bacillus is believed 

 by Klein not to be identical with Pasteur's bacillus of fowl cholera, and is 

 said not to be pathogenic for rabbits, which would seem to differentiate it 

 from this bacillus (Bacillus septicaemias hsemorrhagicae). 



Morphology. Bacilli with rounded ends, from 0.8 to 2 u- long and 

 0.3 to 0.4 it thick ; often in pairs. 



Stains with the usual aniline colors. 



Biological Characters. An aerobic, non-liquefying, non-motile bacillus. 

 Does not form spores. Grows in the usual culture media at the room tem- 

 perature better in the incubating oven. Upon gelatin plates forms grayish- 

 white, superficial colonies, which later present the appearance of flat, homo- 

 geneous, whitish discs with thin edges and irregular margins, and by 

 transmitted light have a brownish color. The deep colonies are small and 

 spherical, and have a brownish color by transmitted light. In gelatin stab 

 cultures a thin, gray layer with irregular margins and of limited extent 

 forms upon the surface, and a scanty growth occurs along the line of punc- 

 ture in the form of a grayish-white line. Upon the surface of agar, at 

 37 C., a thin, gray layer with irregular margins has developed at the end of 

 twenty-four hours ; later this extends over the entire surface as a thin, gray- 

 ish-white layer. No growth occurs upon potato at 37 C. In bouillon, at 37 

 C., development occurs, with clouding of the bouillon, within twenty -four 

 hours; later a deposit consisting of bacilli is seen at the bottom of the tube, 

 but no film forms upon the surface. 



Pathogenesis. Chickens inoculated subcutaneously with a pure culture 

 die in from twenty-four hours to eight or nine days. Pigeons and rabbits 

 are immune. 



BACILLUS CAPSULATUS. 



Obtained by Pfeiffer (1889) from the blood of a guinea-pig which died 

 spontaneously. 



Morphology. Thick bacilli with rounded ends, usually two or three 

 times as long as broad; often united in chains of two or three elements; may 

 grow out into homogeneous filaments. Stained preparations show the ba- 

 cilli to be enveloped in an oval capsule which may be considerably broader 

 than the bacilli themselves two to five times as broad ; where several ba- 

 cilli are united they are surrounded by a single capsular envelope. 



Stains with the usual aniline colors, but not by Gram's method. In pre- 

 parations which are deeply stained with hot f uchsin or gentian violet solu- 



