254 AGRICULTURAL BACTERIOLOGY 



breaks in both animals and man in this country have been 

 caused by animal products from the Orient and South 

 America. 



The disease is primarily one of cattle, sheep, goats, horses, 

 and less frequently hogs. The other common domestic an- 

 imals of our country, cats, dogs, and fowls,, are relatively 

 immune, acquiring the disease only when exposed to large 

 doses of the organism, as is the case when meat from an 

 anthrax carcass is eaten. Man is also susceptible to the 

 disease. He is, however, more resistant to it than are the 

 ruminants, both domestic and wild. 



The disease is variously known in its several forms. The 

 old English term for it was murrain. Splenic fever refers 

 to the enlarged condition of the spleen, while malignant 

 carbuncle refers to the appearance of large swellings on 

 the surface of the body, a common manifestation of the 

 disease in man when the organism has been introduced 

 into wounds. 



Infection. In the case of cattle, sheep, and horses, the 

 portal of entry is most frequently the alimentary tract. It 

 is supposed that the compound stomach of the ruminating 

 animal gives opportunity for the growth of the organism 

 and for the more frequent infection of this type of animal. 

 It seems probable that the organism can, in many cas'-.f- 

 pass through the uninjured wall of the intestine. It is cer- 

 tain that its entrance is made more easy and certain by 

 the presence of wo^i-ds in any part of the alimentary tract. 

 It is probable that abrasion of the mucous surfaces in the 

 mouths of grazing animals or those fed on dry fodder read- 

 ily permits of the entrance of the organism. The transfer- 

 ence of the organism from infectious material and its intro- 

 duction into the body may be accomplished by b : ting flies. 



It is believed that this is the chief way in which the horses 

 and mules of the plantations in the Mississippi delta region 



