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 
