IN THE ANIMAL ORGANISM. 235 



time, by external cooling, unequal quantities of 

 heat. Experience teaches, that if their peculiar 

 temperature and their original weight are to remain 

 unaltered, they require 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 quantity of the constituents of the 

 body, equal in weight to those of the food, has lost 

 its condition of life, and has been expelled in com- 

 bination with oxygen. 



The one individual, which, being exposed to the 

 lower temperature, consumed more food, has also 

 absorbed more oxygen ; a greater quantity of the 

 constituents of its body has been separated in com- 

 bination with oxygen ; and, in consequence of this 

 combination with oxygen, a greater amount of heat 

 has been liberated, by which means the heat ab- 

 stracted has been restored, and the proper tempera- 

 ture of the body kept up. 



Consequently, by the abstraction of heat, provided 



