THE METABOLISM OP THE BODY. 449 



advance physiology, as will shortly appear from our discussion 

 of the influence of the nervous system on the various metabolic 

 processes generally. 



The phenomena observable in an animal gradually freezing 

 to death point strongly to the direct influence of the nervous 

 system on the production as well as the regulation of heat. 

 The circulation must of course be largely concerned, but it ap- 

 pears as though the nervous system refused to act when the 

 temperature falls below a certain point. A low temperature 

 favors hibernation, in which we believe the nervous system 

 plays the chief part, though the temperature in itself is not the 

 determining cause, as we have ourselves proved. The fact that 

 the whole metabolism of a hibernating animal is lowered, that 

 with this there is loss of consciousness much more profound 

 than in ordinary sleep, of itself seems to indicate that the nerv- 

 ous system is at the bottom of the whole matter. 



Pathological. — It is found that many drugs and poisons 

 lower temperature, acting in a variety of ways. In certain dis- 

 eases, as cholera, the temperature may sink to 33° C. in extreme 

 cases before death supervenes. When the temperature of the 

 blood is raised 6° to 8° C. (as in sunstroke, etc.), death occurs ; 

 and it is well known that prolonged high temperature leads to 

 fatty degeneration of the tissues generally. All the evidence 

 goes to show that in fever both the heat production and the 

 heat expenditure are interfered with ; or, at least, if not always, 

 that there may be in certain cases such a double disturbance. 

 In fever excessive consumption of oxygen and production of 

 carbon dioxide occur, the metabolism is quickened, hence its 

 wasting (consuming) effects ; the rapid respiration tends to in- 

 crease the thirst, from the extra amount of aqueous vapor ex- 

 haled. The body is actually warmest during the " cold stage " 

 of fever, when the vessels of the skin are constricted and the 

 patient feels cold, because the internal metabolism is heightened ; 

 while the " sweating stage " is marked by a natural fall of tem- 

 perature. The fact that the skin may be dry and pale in fever 

 shows that the thermotaxic nervous mechanism is at fault; but 

 the chemical facts cited above (excess of COa etc.) indicate that 

 the thermogenic mechanism is also deranged. 



