157 



Geographical Distribution. 



Anthrax is known over practically the whole world, its preva- 

 lence being influenced only partly by heat and cold, but princi- 

 pally by the amount of moisture required for the development 

 and propagation of the bacillus. In the United States anthrax 

 districts have been known along the lowlands and river bottoms 

 in all of the Gulf States; Missouri, for instance, having suffered 

 from periodical outbreaks ever since 1836. Anthrax is a dis- 

 ease of the spring and summer months, though cases may occur 

 at all times of the year. 



The cause of the disease is, as stated, the anthrax bacillus, a 

 comparatively large rod-shaped micro-organism, which, in dried 

 specimens, appears to have absolutely square ends. This feature 

 is believed to be characteristic of the anthrax bacillus alone, all 

 other rod-shaped micro-organisms having more or less rounded 

 ends. 



The bacillus multiplies by fission, whereby chains, resembling 

 a stick of bamboo, are formed. It grows readily in milk, bouillon 

 and other culture media, while blood offers the most favorable op- 

 portunity for its rapid development. W/hen placed under unfa- 

 vorable conditions the l3acillus forms spores or seeds, which are 

 very resistant to all destructive agents and may remain quiescent 

 for long periods of time, but which, when again favored by heat 

 and moisture, will develop into virulent bacilli, which, as soon as 

 they gain entrance into the body of susceptible animals, may 

 cause anthrax to break out. 



Animals Affected. 



Practically all domestic animals as well as human beings may 

 contract the disease, though with a varying degree of suscepti- 

 bility, both as regards species and individuals. The plant-eating 

 animals, for instance, are very susceptible, while meat-eating 

 ones are less so. Cattle and sheep, being ruminants, are ex- 

 tremely susceptible, and as a rule contract the fulminating or 

 apoplectiform type of the disease, while horses and mules fre- 

 quently live several days, exhibiting the local and skin form, and 

 some cases recover. Cattle and sheep, which seemed well when 

 last seen or fed at night, are usually found dead in the morning, 

 while horses and mules may show extensive swellings around the 

 throat and neck and may live for several days before succumbing 

 to the disease. Swine are much less susceptible, but may de- 

 velop the disease after feeding on anthrax carcasses. Dogs and 

 cats are quite immune to the disease, but may contract it after 

 partaking of large portions of anthrax-infected carcasses. All 

 of these latter animals develop the form known as gloss anthrax, 

 which is characterized by swellings and discoloration along the 

 throat and neck, difficulty in swallowing, vomiting, profuse bloody 

 diarrhoea, high fever and death. 



