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BACILLUS OF MOUSE SEPTIC^MIA. 

 Koch (18T8J. 



SYNONYMS. BACILLUS MURISEPTICUS. MAUSESEPTIKAMIE (Germ.). 



Origin. From mice after inoculation with putrid blood. 



Form. The rods are narrower and thinner than those of the 

 rouget bacillus, but otherwise resemble the latter very much. 



Motility. Appears to possess motion. Said to be non-motile 

 by some. 



Sporulaticn. Round, glistening bodies, or spores form within 

 the cells. 



Anilin Dyes. Stain rapidly. Gram's method is applicable. 



Growth. Is rather slow and resembles very closely that of 

 the rouget bacillus. 



Plates. The colonies on the gelatin plate resemble those of the rouget 

 bacillus, except that they spread somewhat more rapidly and are especially 

 delicate and transparent in appearance. 



Stich Cultures. Show this distinction in growth quite sharply. While 

 the cloudy growth of the rouget bacillus is dense and somewhat limited to the 

 line of inoculation, that of the mouse septicaemia bacillus spreads readily 

 throughout the entire gelatin. This difference is clearly seen in young 

 cultures. 



Streak Cultures. On agar the growth is scarcely to be distinguished 

 from that of the rouget bacillus. 



Bouillon The bacillus develops a growth similar to that of the bacillus 

 of rouget. 



Oxygen requirements. Is a facultative aerobe. Grows better 

 when air is excluded. 



Temperature. Grows well at ordinary temperature, also in 

 the incubator. 



Behavior to Gelatin. Ordinarily no liquefaction can be ob- 

 served. Sometimes, however, it is present. 



Aerogenesis. Produces less hydrogen sulphide than the rou- 

 get bacillus. 



Attenuation Old cultures possess diminished virulence. 



Immunity. Rabbits that recover after one inoculation with 

 the pure culture are rendered immune against subsequent inocula- 

 tion. 



Fathogenesis. White mice, house mice, pigeons, sparrows 

 and rabbits are susceptible. Chickens, guinea-pigs and field mice are 

 wholly immune. After death the bacilli are distributed throughout 

 the body, single or in pairs, and frequently inclosed in cells. 



