OF ANIMAL HEAT. 85 



after deducting the necessary amount of heat, 

 146380-4 degrees of heat, which are dissipated by 

 radiation, by heating the expired air, and in the ex- 

 crementitious matters. 



In this calculation, no account has been taken of 

 the heat evolved by the hydrogen of the food, during 

 its conversion into water by oxidation within the 

 body. But if we consider that the specific heat of 

 the bones, of fat, and of the organs generally, is far 

 less than that of water, and that consequently they 

 require, in order to be heated to 98*3°, much less 

 heat than an equal weight of water, no doubt can 

 be entertained, that when all the concomitant cir- 

 cumstances are included in the calculation, the heat 

 evolved in the process of combustion, to which the 

 food is subjected in the body, is amply sufficient to 

 explain the constant temperature of the body, as 

 well as the evaporation from the skin and lungs. 



VI. All experiments hitherto made on the quan- 

 tity of oxygen which an animal consumes in a given 

 time, and also the conclusions deduced from them 

 as to the origin of animal heat, are destitute of 

 practical value in regard to this question, since we 

 have seen that the quantity of oxygen consurned 

 varies according to the temperature and density of 

 the air, according to the degree of motion, labour, 

 or exercise, to the amount and quality of the food, 

 to the comparative warmth of the clothing, and also 

 accordina: to the time within which the food is taken. 

 Prisoners in the Bridewell at Marienschloss (a prison 



d2 



