QUANTITY OF FOOD REGULATED. 21 



In cold and temperate climates, the air, which inces- 

 santly strives to consume the body, urges man to labori- 

 ous efforts in order to furnish the means of resistance to 

 its action, while, in hot climates, the necessity of labor 

 to provide food is far less urgent. 



Our clothing is merely an equivalent for a certain 

 amount of food. The more warmly we are clothed the 

 less urgent becomes the appetite for food, because the 

 loss of heat by cooling, and consequently the amount 

 of heat to be supplied by the food, is diminished. 



If we were to go naked, like certain savage tribes, or 

 if in hunting or fishing we were exposed to the same 

 degree of cold as the Samoyedes, we should be able 

 with ease to consume 10 Ibs. of flesh, and perhaps a 

 dozen of tallow candles into the bargain, daily, as warm- 

 ly clad travellers have related with astonishment of these 

 people. We should then also be able to take the same 

 quantity of brandy or train oil without bad effects, be- 

 cause the carbon and hydrogen of these substances 

 would only suffice to keep up the equilibrium between 

 the external temperature and that of our bodies. 



According to the preceding expositions, the quantity 

 of food is regulated by the number of respirations, by 

 the temperature of the air, and by the amount of heat 

 given off to the surrounding medium. 



No isolated fact, apparently opposed to this statement 

 can affect the truth of this natural law. Without tem- 

 porary or permanent injury to health, the Neapolitan 

 cannot take more* carbon and hydrogen in the shape of 

 food than he expires as carbonic acid and water ; and 



