856 PYREXIA. [BOOK n. 



animals or on parts of the bodies of larger animals and of man are 

 not wholly accordant. There is a general agreement that the 

 initial rise of temperature is accompanied by, and in part at 

 least due to, a diminution of loss of heat ; and in a similar way 

 the fall of temperature at the end of fever is, in many cases at least, 

 accompanied by an increase in the loss of heat. Further, in some 

 cases of transient pyrexia artificially produced in animals by the 

 injection of fever-giving material, of certain micro-organisms for in- 

 stance, the calorimeter has shewn no increase in the production of 

 heat; the fever in such cases seems to have been due to diminished 

 loss of heat. On the other hand other observations on other cases 

 seem to shew that in these the continued high temperature is 

 in the main due to increased production. This latter conclusion 

 is moreover apparently supported by observations which shew that 

 during fever, the production of carbonic acid, and the consumption 

 of oxygen, that is to say, the metabolic changes of the tissues, 

 are increased. The urea also is increased, and that in such a way 

 as to confirm the view already expressed that much of the heat 

 comes from such a metabolism of the skeletal muscles as, unlike 

 an ordinary contraction, directly involves the nitrogenous elements. 

 The inordinate metabolism of the body at large thus characteristic 

 of fever is shewn by the wasting which it entails. But this argu- 

 ment must be used with caution, since a high continued temperature 

 even though brought about essentially by a diminution of the loss 

 of heat, would unless checked by some restraining influences, of 

 a nervous or other nature, tend of itself to increase metabolic 

 changes ; and it might be urged that such an abnormal metabolism 

 might be different in character from that taking place in a normal 

 way. On the whole however the evidence seems to be in the 

 direction of shewing that the rise of temperature in fever is largely 

 due to increased production. We may add that the lowering of 

 . temperature brought about in fever by so called antipyretic drugs 

 such as antipyrin is shewn by the calorimeter to be chiefly due to 

 an increased loss of heat. 



In some maladies the bodily temperature falls distinctly below 

 the normal average, reaching for instance 35 or even lower. In 

 such cases there can be little doubt that the condition is due to 

 diminished metabolism and diminished heat production. 



One of the most marked phenomena of starvation is the fall of 

 temperature, which becomes very rapid during the last days of life. 

 The lowered metabolism diminishes the production of heat, and .the 

 lowered temperature in turn still further diminishes the meta- 

 bolism. Indeed the low temperature is a powerful factor in bringing 

 about death, for life may be much prolonged by wrapping a starving 

 animal in some bad conductor so as to economise the bodily heat. 



538. Effects of Great Heat. As we said above, the regulative 

 heat mechanism is unable to withstand the strain of too great an 

 external heat or too prolonged an exposure to a great but less 



