PATHOGENIC BACTERIA. 333 



for forty days, and i-iooo bichloride of mercury for nearly 

 three days. The anthrax bacillus is aerobic, although not 

 strictly so. It stains by Gram's method. It grows at the 

 room temperature, but better in the incubator. It liquefies 

 gelatin and coagulated blood-serum. Colonies in gelatin seen 

 under a low power display numerous, irregular, fine, hair-like 

 projections; stab-cultures in gelatin also present fine projec- 

 tions passing from the needle-puncture into the solid gelatin. 

 It grows on the ordinary culture-media; the growths are usually 



Fig. 82. — Colony of anthrax bacilli (low power), from an impression 

 preparation stained with methplene blue. 



whitish. Cultures on potato kept in the incubator are favor- 

 able to the development of spores. Milk is coagulated and 

 and later peptonized. 



It is pathogenic for mice, guinea-pigs, rabbits, cats, certain 

 carnivora and a great many other animals; it is also specially 

 pathogenic for sheep and cattle. Rats and pigeons are quite 

 resistant, but not entirely immune; dogs and frogs are not sus- 

 ceptible, or but slightly so. 



Anthrax is a disease which occurs spontaneously chiefly in 

 cattle and sheep. It is commoner on the continent of Europe 

 and in Siberia than in America. In susceptible animals in- 



