ANTHRAX OR SPLENIC FEVER. 283 



animals dead from anthrax have been buried, and the spores have 

 remained alive for many years. Now, although these spores may 

 have been buried some distance below the surface, they are event- 

 ually brought to the surface. One of the means by which they are 

 brought up from under ground is through the agency of earth- 

 worms, and the spores are later taken into the stomachs of cattle 

 feeding on the grass. These spores resist the action of the di- 

 gestive juices and of the other bacteria present in the intestine, and 

 make their way through the intestinal walls into the body, producing 

 the disease. These facts readily explain many of the phenomena 

 connected with the outbreaks of epidemics. 



In other cases the germs may find entrance through abrasions of 

 the skin. When thus introduced the bacteria first produce a simple 

 abscess in the skin, which soon turns into a gelatinous pustule. 

 This pustule does not heal, and from it as a center the bacilli spread 

 rapidly through the body, producing a general disease which may 

 terminate fatally. The name malignant pustule is appropriately 

 applied to this form of disease. In susceptible animals such re- 

 covery is very rare. In the case of animals which, like man, are 

 less susceptible to the disease, these abscesses may remain simple 

 localized infections, eventually healing without spreading through the 

 body. There are other modes of infection, but among animals the 

 disease is most usually acquired through the intestine or through 

 skin abrasions. 



In the body of the infected animals the bacilli grow with great 

 rapidity. An extremely small number of them inoculated into the 

 body of a sheep may produce its death in about two days, and after 

 death the whole body is found to be filled with the bacilli in incal- 

 culable numbers. The disease is marked by a high fever and much 

 discomfort, and after death the most characteristic symptom is a 

 greatly swollen spleen, whence the name splenic fever. The spleen 

 is large, hard, and brittle, and contains enormous numbers of the 

 bacilli. The blood-vessels are also found to be full of them, and the 

 capillaries may literally be crammed with bacteria. 



This bacillus is extremely virulent in its action upon susceptible 

 animals, so virulent, indeed, that a single bacillus, inoculated 



