INFECTIOUS FEVERS OF SWINE. 



One name for several affections. Differentiation, swine erysipelas, hog 

 cholera and swine plague. Complex infections. Effects of large, medium 

 and small doses, of more or less potent germ, of greater or less suscepti- 

 bility. 



Until comparatively recent years the variou.s infectious fevers 

 of swine have been confounded and described as a single disease, 

 the name varying in the different countries in which they were 

 observed. In America it was .^o^ C^o/^ra / in England, Swine 

 Fever; in France, Jiougei / andin Germsiny, ScAzveineseuche. A 

 closer study showed a marked tendency to a particular class of 

 lesions in different epizootics, and bacteriological research associ- 

 ated plagues in given localities with different microbes, so that 

 progress has been made in differentiating one from another to a 

 certain extent. 



The first clear distinction was made in setting aside the swine 

 ery.sipelas (rouget, rothlauf,) from the r&st as distinguished at 

 once by its small, delicate bacillus, differing notably from the 

 others in its staining and cultural peculiarities, as well as in the 

 predominance of the cutaneous lesions. 



What remains after eliminating erysipelas, constitutes a group 

 having so much in common that attempts at further differentiation 

 have led to much di,sputation, and not even to-day is there such 

 accord in different countries as the writer of a text-book would 

 find desirable. One class of pathologists claims but one common 

 disease with many varieties under different conditions, just as the 

 term septiccsmia or blood poisoning has been made to designate a 

 whole class of local and general infections, irrespective of the 

 particular microbes that cause them. Others with greater pre- 

 cision give the disease a name according to the causation by one 

 particular microorganism, or by another, which may be closely 

 related to it in many respects, but which in successive subjects 

 and. outbreaks, maintains its own individual characteristics as re- 

 gards morphology, cultural and staining habits, pathogenesis, etc. 

 The question has been rendered all the more trying, by the occa- 

 sional association in the same animal system, or in the same 



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