PATHOGENIC BACTERIA. 273 



stand boiling for twelve minutes,* 5 per cent, carbolic acid 

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

 three days. The anthrax baciUus 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 pro- 

 jections; stab-cultures in gelatin also present fine projections 

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

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



Fig. 77. — Colony of Anthrax Bacilli (Low Power). 



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

 vorable to the development of spores. Milk is coagulated 

 and later peptonized. 



It is pathogenic for mice and guinea-pigs, less so for rab- 

 bits; it is also pathogenic for sheep and cattle. Rats and 

 pigeons are quite resistant, but not entirely immune; cats, 

 dogs and frogs are not susceptible, or but slightly so. 



Anthrax is a disease which occurs chiefly in cattle and sheep. 

 It is commoner on the continent of Europe and in Siberia than 



1902 



* More than half an hour. V. A. Moore. Infectious Diseases oj Animals. 



