IN SUSCEPTIBLE ANIMALS. 431 



surface ; after the eighth day liquefaction progresses more rapidly. About 

 the sixth day a bright-green color is recognized in the upper part of the tube 

 by reflected light. Upon agar plates, at 37 0. , at the end of forty-eight 

 hours minute colonies are formed, of irregular form, which have a white 

 color with a shade of green ; in older colonies the central portion may be 

 finely granular and brownish yellow in color, while the marginal zone is 

 more transparent ; the agar has by reflected light a deep emerald green color. 

 In agar stick cultures, at the end of twenty hours, an abundant development 

 has occurred without color ; at the end of forty-eight hours the culture me- 

 dium is of a bright green color throughout ; later the color changes to brown. 

 A dirty-yellow layer forms upon the surface of the agar. Upon potato, at 

 37 C., a dark-brown layer forms in the vicinity of the line of inoculation; 

 later this is chocolate brown. 



The cultures in gelatin and agar give off a peculiar, penetrating odor 

 similar to that of jasmin. 



Pathogenesis. Pathogenic for rabbits when injected into a vein or sub- 

 cutaneously. Death occurs in from thirty- six to forty- eight hours. At the 

 autopsy haemorrhagic extravasations are found beneath the pericardium and 

 the pleuras ; abscesses in the lungs and liver. The bacilli are found in the 

 blood and in the various organs in large numbers. 



79. BACILLUS PNEUMOSEPTICUS. 



Obtained by Babes (1889) from the blood and tissues of an individual who 

 died of septic pneumonia. 



Morphology. Small, straight bacilli about 0.2 n thick. 



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



Biological Characters. An aerobic and facultative anaerobic, non-lique- 

 fying, non-motile bacillus. Spore formation not observed. Grows in the 

 usual culture media at the room temperature. Upon gelatin plates superfi- 

 cial colonies are formed which are flat, irregular in outline, whitish, shining, 

 and semi transparent ; under a low power finger- like offshoots are seen about 

 the periphery. In gelatin stick cultures an abundant development occurs 

 along the line of puncture; the colonies give off a strong sperm-like odor. 

 Upon the surface of agar small, whitish, flat, shining colonies with ill de- 

 fined outlines are formed, which soon become confluent and cover the sur- 

 face ; an abundant white deposit is seen in the condensation water. Upoti 

 potato a moist, white layer is formed. Upon blood serum circular, whitish, 

 transparent colonies are formed along the line of inoculation, which soon 

 coalesce. 



Pathogenesis. Very pathogenic for rabbits, guinea-pigs, and mice when 

 injected subcutaneously in small amount. The animals die in from two to 

 three days without any noticeable local inflammation and with symptoms of 

 septicaemia. The lungs and spleen are found to be hyperaamic. The bacilli 

 are found in the blood free, or sometimes enclosed in the leucocytes ; they 

 are only found in small numbers in the capillaries of the internal organs. 

 Cultures gradually lose their virulence when propagated ia artificial media. 



80. 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 fuchsin or gentian violet solu- 



