IN THE ANIMAL ORGANISM. 223 



By the combination of oxygen with the constituents 

 of the metamorphosed tissues, the temperature ne- 

 cessary to the manifestations of vitality, is produced 

 in the carnivora. In the herbivora, again, a certain 

 amount of heat is developed by means of those ele- 

 ments of their non-azotized food, which have the prop- 

 erty of combining with oxygen. 



It is obvious, that the temperature of an animal body 

 cannot change, if the amount of inspired oxygen in- 

 creases in the same ratio as the loss of heat by external 

 cooling. 



Two individuals, carnivora, of equal weight, ex- 

 posed to unequal degrees of cold, lose, in a given time, 

 by external cooling, unequal quantities of heat. Ex- 

 perience teaches, that if their peculiar temperature and 

 their original weight are to remain unaltered, they re- 

 quire unequal quantities of food ; more in the lower 

 temperature than in the higher. 



The circumstance, that the original weight remains 

 the same, with unequal quantities of food, obviously 

 presupposes, that in the same time a quantity of oxygen 

 proportional to the temperature has been absorbed ; 

 more in the lower than in the higher temperature. 



We find that the weight of both individuals, at the 

 end of 24 hours, is equal to the original weight. But 

 we have assumed that their food is converted into blood ; 

 that the blood has served for nutrition ; and it is plain, 

 that when the original weight has been restored, a quan- 

 tity of the constituents of the body, equal in weight to 



