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the animal's body of a bacterium, or its spores. Practically all ani- 

 mals are susceptible to anthrax. The herbivora are especially sus- 

 ceptible, in the following order: The sheep, the ox, and the horse. 

 The guinea pig, the hog, the rabbit, mice and other animals die 

 quickly from its effects. Man, the dog, and other omnivora and 

 carnivora may be attacked by it in a constitutional form as fatal as 

 in the herbivora, but fortunately, in many cases, develop from it 

 only local trouble, followed by recovery. 



Causes. The causes of anthrax were for a long time attributed 

 entirely to climatic influence, soil, and atmospheric temperature, 

 and they are still recognized as predisposing factors in the develop- 

 ment of the disease, for it is usually found, especially when out- 

 breaks over any number of animals occur, in low, damp, marshy 

 countries during the warm seasons. It is more frequent in districts 

 where marshy lands dry out during the heat of summer and are 

 then covered with light rains. Decaying vegetable matter seems 

 most favorable for nourishing and preserving the virus. The direct 

 cause of anthrax is always infection of a previously sound animal, 

 either directly from a diseased animal or through various media 

 which contain execretions or the debris from the body of the previ- 

 ously infected animal. 



The specific virus of anthrax was first discovered in 1851. It 

 was not, however, till a quarter of a century later that the exact 

 nature of the bacillus, the mode of its propagation, and its exact 

 relationship to anthrax as the sole cause of the disease was defined. 

 In the animal body the bacilli have a tendency to accumulate in 

 the spleen, liver, and elsewhere, so that these organs are much more 

 virulent than the muscles or less vascular tissues. When eliminated 

 from the animal in the excretions, or when exposed to outside in- 

 fluences by the death of the animal and the disintegration of the 

 tissues, the body of the rod is destroyed and the spores only remain. 

 These spores, which may be called the seeds of the bacilli, retain 

 their vitality for a long period ; they resist ordinary putrefaction ; 

 they are unchanged by moisture ; and they are not affected by mod- 

 erate heat. If scattered with the debris of >a dead animal on the 

 surface of the ground, they may remain around the roots of the 

 grass in a pasture or may be washed to the nearest low-lying ground 

 or marsh. If buried in the body of an animal dead from anthrax, 

 they may be washed deep into the ground, and in later years (in 

 one proven case 17 years) be brought to the surface and infect other 

 animals. They are frequently brought to the surface of the earth, 

 having been swallowed by earthworms, in the bodies of which they 

 have been found. 



This accounts for the outbreaks at the time of the first rains 

 after a dry season. During the latter the earthworm goes deep in 

 the ground in search of moisture ; it finds the spore which has been 

 washed there in past years, swallows it, and afterwards brings it 

 to the surface. The virus is carried with the wool from infected 

 sheep and remains in it through the process of manufacture into 

 cloth. The spores remain in the hides of animals which have died 



