142 PRINCIPLES OF VETERINARY SURGERY 



Description. — Non-motile. Non-flagellated. Sporogen- 

 ous. Non-chromogenic. Liquefying. Aerobic. Patho- 

 genic. Size, 5 /". to 20 /x long by 1 /a to 1.25 1^ thick. It is a 

 very large bacterium, which fact facilitated its early discov- 

 ery. It has a very pronounced tendency to grow into long 

 threads which distinctly show the separate bacilli, each of 

 which is rectangular and somewhat rounded at the ends. 

 The sporulation is always prolific, each spore forming at or 

 very near the center of the rod, without increasing its dia- 

 meter at the point of formation. The spore increases in 

 length only, and finally ruptures to release the new bacillus. 



Cultivation. — The bacillus may be grown on agar-agar, 

 gelatin, potato and blood serum and in milk and bouillon. 

 The growth is most active at the temperature of the body, 

 but is not arrested in an environment as low as 68° Fahr., 

 nor as high as 112° Fahr. 



Staining. — The bacillus takes Gram's and AA'eigert's and 

 can also be colored with the ordinary acjueous anilin solu- 

 tions. The spores are stained with carbol-fuchsin, after 

 which the remaining parts of the bacilli are decolorized 

 with a weak acid and then re-stained with methyl blue. 



Isolation. — The bacillus anthracis is an excellent speci- 

 men for studying the behavior of micro-organisn:s, and their 

 resistance to antiseptics. Other bacteria are constantly 

 compared with it as regards size, sporulation, thread-forma- 

 tion and resistance to chemical and thermic actions It is 

 easily isolated on account of its size, appearance of the colo- 

 nies, and the receptivity of the experimental animals, by 

 making smear-cultures or by inoculation of an animal and 

 obtaining it from the blood. 



Pathogenicity. — Infection occurs through the alimentary 

 tract or through wounds in the surface of the body. The 

 respiratory tract is always referred to as a channel of en- 

 trance, owing to the "wool-sorter's disease" it producer. 



