Dysentery of Cattle. 245 



It is well recognized as a disease of the ox, and the older writ- 

 ers allege its existence also in horses, swine and dogs, though 

 this is not admitted in all modern veterinary works. 



Causes. It was formerly ascribed to improper hygiene, chills, 

 cold rain storms, night dews, hoar frost, malarious emanations, 

 putrid, stagnant or iced water, irritants in food, green, fermented 

 or musty food, a too liberal diet after starvation, overtaxation in 

 very hot weather, and bad odors from decomposing carcasses. 

 These can only be accepted as predisposing causes begetting a 

 general debility, or debility of the alimentary canal and laying 

 that open to the attacks of specific microbes. The close aggrega- 

 tion of cattle on ship-board, in besieged cities, and in the parks 

 of armies in the field, has apparently contributed to the propaga- 

 tion of the dysentery. The removal of a victim to a herd with 

 free healthy range seldom starts a new center of the disease. In 

 all infected herds huddled in small compass there is every facility 

 for a propagation of a germ already present, and especially in 

 the commissariat of a belligerent army there are enough privations, 

 over-exertions and other trying conditions to favor predisposition. 

 Faulty food like stale bread, musty hay, have been supposed to 

 cause it. For man and beast alike dvsentery is preeminently a 

 disease of the tropics, and of hot seasons, and will often subside on 

 the advent of cold weather. 



Its propagation on given (swampy) soils, and in particular (foul) 

 stables strongly suggests a special germ, though for the cow this 

 has not been perfectly identified. Gerlach vainly attempted 

 to inoculate it, and it does not often propagate itself beyond 

 the foul and infected localities or stables, yet its persistence in 

 them for years bespeaks unequivocally the operation of a special 

 pathogenic ferment. 



It may also be fairly assumed that it is not necessary that the 

 same factor should be present in all cases alike, but that one 

 operates predominantly in one case and another in another. In 

 other words dysentery must be recognized as not one disease, but 

 several, of which the true pathogenic microbes have not yet been 

 fully demonstrated, but which are classed together because of the 

 similarity of the attendant lesions. 



In man three distinct forms are recognized. 1. Catarrhal 

 dysentery, with frequent small stools of rosy mucus, and blood ; 



