PRiMclptES 6F YMtERIMaRY StfRfiERY 55 



to the heat of inflammation. It was supposed that the in- 

 flammatory process generated heat and that the heat diffused 

 through the entire organism. This hypothesis was not long 

 entertained because the amount of heat in a local inflamma- 

 tory condition is always insufficient to elevate the tempera- 

 ture to any considerable extent, and especially, because there 

 is no reg-ular relation between the degree of fever and the in- 

 tensity or extent of the local inflammations, which do not in 

 themselves, produce heat. It has also been supposed that 

 fever is an inflammation of the blood, — a haemitis. The the- 

 ory was evidently based upon the perceptible changes in the 

 blood in fever cases, which are now known to be due to 

 micro-organisms and combustion products. Woods states 

 that "There are- nerve centers which are directly con- 

 cerned in the thermogenic function and which af- 

 fect the production of animal heat independently of the cir- 

 culation, by direct action upon the tissues." Besides the 

 theories above mentioned there is the bacterial theory of the 

 modern pathologists, which will account well enough for 

 many febrile states but which can not be accepted as the 

 universal cause in the face of the fact that many febrile con- 

 ditions are known to be provoked by conditions in which 

 bacteria play no part. Fever can be experimentally pro- 

 duced in animals by inoculation with pus, purulent products 

 and certain microbian cultures, but it can also be produced 

 by chemical substances. The fever caused experimentally 

 by microbian inoculation, does not, however, like that of 

 chemical agents, depend upon the amount injected. The 

 virulence of the inoculated virus is a more potent factor than 

 the amount. 



The part played by bacteria in the production of fever is 

 still not satisfactorily explained. Whether they or their 

 toxins simply disturb the nervous system, or produce 

 changes in the blood and tissues which directly augment 



