56 PRINCIPLES OF VETERINARY SURGERY 



heat generation, is not known. It is, however, positively 

 known that fever produced by chemical substances, by fear, 

 by shock, or any external cause is not lasting, and that the 

 only really persisting febrile states found in animals, are per- 

 petuated if not caused by the influence of micro-organisms. 

 In this connection Warren says : "In general it may be 

 said that fever is due to the presence in the blood of a pyro- 

 genous substance of an organic nature, that may have been 

 produced by bacteria ; or to the presence of bacteria ; or 

 finally to some ferment-like substance which has resulted 

 from cell-disintegration." When such eminent writers as 

 Warren will not take a positive stand as to the exact role of 

 micro-organisms in the causation of fever, it may be safely 

 concluded that the matter is not definitely settled. A few 

 years ago writers on surgery referred to all obscure surgical 

 fevers as the result of impressions on the nervous system, 

 and even today the term "aseptic fever" is by no means obso- 

 lete. The fever that follows in the wake of an apparently 

 aseptic operation is conveniently attributed to nervous dis- 

 turbances, or to the absorption of entirely harmless products 

 in small c^uantities, proceeding from the wounded tissues. 

 It is, however, interesting to note that these so-called "aseptic 

 febrile states" are becoming fewer and fewer as surgical com- 

 plications are becoming better understood. It is pretty safe 

 for the present-day veterinarian to act under the cjuite log- 

 ical deduction that fever in surgery is synonymous with mi- 

 crobian infection. In a word, fever in veterinary pathology 

 is caused by micro-organisms, by their toxins, or by both. 



Fever has also been described as nature's protection 

 against microbian invasion, the supposition being that either 

 the high temperature or the morbid condition responsible for 

 it were inimical to the welfare of the intruding micro-organ- 

 isms. This the'ory is entirely without any foundation to sup- 

 port it, except the fact that attempts to lower the body tern- 



