A HISTORY OF SCIENCE 



than in Sicily; and in our more temperate climate a 

 full eighth more in winter than in summer. 



" Even when we consume equal weights of food in 

 cold and warm countries, infinite wisdom has so ar- 

 ranged that the articles of food in different climates 

 are most unequal in the proportion of carbon they 

 contain. The fruits on which the natives of the South 

 prefer to feed do not in the fresh state contain more 

 than twelve per cent, of carbon, while the blubber 

 and train-oil used by the inhabitants of the arctic 

 regions contain from sixty-six to eighty per cent, of 

 carbon. 



" It is no difficult matter, in warm climates, to study 

 moderation in eating, and men can bear hunger for a 

 long time under the equator; but cold and hunger 

 united very soon exhaust the body. 



"The mutual action between the elements of the 

 food and the oxygen conveyed by the circulation of 

 the blood to every part of the body is the source of 

 animal heat. 



"All living creatures whose existence depends on 

 the absorption of oxygen possess within themselves a 

 source of heat independent of surrounding objects. 



"This truth applies to all animals, and extends be- 

 sides to the germination of seeds, to the flowering of 

 plants, and to the maturation of fruits. It is only in 

 those parts of the body to which arterial blood, and 

 with it the oxygen absorbed in respiration, is conveyed 

 that heat is produced. Hair, wool, or feathers do 

 not possess an elevated temperature. This high tem- 

 perature of the animal body, or, as it may be called, 

 disengagement of heat, is uniformly and under all cir- 



