ETIOI.OGY 



83 



Eastern and Central Africa, where in recent years it has become 

 a great plague. In Siberia it has caused fearful destruction, 

 and in that country it is still known as the "Siberian Plague." 

 It has frequently appeared in England. Russia, India and 

 Australia are also infected. In the United States, it has been 

 reported from at least fifteen states and territories. In fact 

 there are very few, if any, countries where this disease has not 

 been found. In the eastern part of this country it exists to a 

 greater or less extent in certain localities. A knowledge of 

 its .specific cause with the methods of properly disposing of 

 dead animals, isolation and disinfection as well as the pre- 

 ventive inoculations now in vogue, have made it possible to 

 prevent widespread epizootics. In America it is looked upon 

 as a comparatively rare disease, excepting in certain infected 

 districts. 



§ 74. Etiology. An- 

 thrax is due to the effect of 

 the presence of a specific 

 micro-organism known as 

 Bacterium {Bacilhis^ an- 

 thracis. This organism is 

 found in the diseased tissues 

 and organs of affected ani- 

 mals. On account of its 

 spores, it is very resistant 

 to the normal destructive 

 agencies in nature. Con- 

 sequently when it is once 

 introduced into a locality it p^^. 10. Anthrax bacteria from an 



tends to remain there for impression preparation from a colo^iy. 

 many years, possibly causing from time to time a few cases of 

 anthrax or serious epizootics or epidemics. The spores are 

 also frequently carried in the wool, hair, hide, hoofs and horns 

 taken from animals sick or dead of anthrax. Thus the affec- 

 tion has been introduced into far distant localities. 



Bacterium anthracis is a rod-shaped organism varying in 

 length from i to 4//, but having a quite uniform breadth of 

 about one micron. In a suitable medium it grows out in long 



