BACILLUS ANTHRACIS. 315 



thirty-six hours. 



For the differential diagnosis between symptomatic 

 anthrax and malignant edema, see page 314. 



It may be difficult to differentiate an anthrax bacillus 

 from soil from the closely related spore-forming varieties. 

 If a virulent form is in question, then the inoculation 

 with a sample of earth into several guinea-pigs will often 

 decide the question. The dead animals will be examined 

 as described above. Thus it is possible that one animal 

 dies of anthrax, others of malignant edema, tetanus, etc., 

 the causes of which were all present as spores in the 

 sample of soil. Non-virulent forms of anthrax, isolated 

 from soil, are only recognizable by comparison with known 

 anthrax, whereby the five species of the table (p. 314) are 

 to be excluded. 



The following are described as closely related to anthrax: 



B. pseudanthracis Burri. According to Hartleb and 

 Stutzer, it is widely distributed in American meat powder. 

 The cultures isolated from different samples were not ex- 

 actly identical. The cultures are motile, especially when 

 grown in bouillon. Also it is important that in bouillon 

 there is first diffuse turbidity, then a clearing up, with the 

 formation of a precipitate and pellicle. All other charac- 

 teristics are deceptively like those of anthrax. Its viru- 

 lence for mice and guinea-pigs is slight. Compare C. B. 

 L. in, 81, where also is a description of cultures of B. 

 pseudanthracis II and III, which are still a little further 

 removed from anthrax. 



B. anthracoides Hiippe and Wood (from soil), which 

 we obtained from Krai and carefully studied. We found, 

 indeed, the agar cultures macroscopically very much 

 like anthrax, but microscopically they resemble B. sub- 

 tilis; also upon gelatin the similarity to Bac. subtilis 

 when magnified 60 times was much greater than to Bac. 

 anthracis. In young colonies loop-like projections extend 

 out, reminding one of Bact. vulgare. When magnified 

 1000 times, sluggish motion was unmistakable. 



B. anthraci similis McFarland (C. B. xxiv, 556). It 

 was once found upon a laboratory plate, and is entirely 

 non-pathogenic. Perhaps it was true anthrax. 



