24 HYDROGEN CONTRIBUTES 



have sufficient power to place the diminished amount 

 of food in equilibrium with the inspired oxygen ; in 

 the colder climate, the organs of respiration them- 

 selves would have been consumed in furnishing the 

 necessary resistance to the action of the atmospheric 

 oxygen. 



In our climate, hepatic diseases, or those arising 

 from excess of carbon, prevail in summer ; in winter, 

 pulmonic diseases, or those arising from excess of 

 oxygen, are more frequent. 



The cooling of the body, by whatever cause it 

 may be produced, increases the amount of food 

 necessary. The mere exposure to the open air, in 

 a carriage or on the deck of a ship, by increasing 

 radiation and vaporization, increases the loss of heat, 

 and compels us to eat more than usual. The same 

 is true of those who are accustomed to drink large 

 quantities of cold water, which is given off at the 

 temperature of the body, 96'5. It increases the 

 appetite, and persons of weak constitution find it 

 necessary, by continued exercise, to supply to the 

 system the oxygen required to restore the heat 

 abstracted by the cold water. Loud and long con- 

 tinued speaking, the crying of infants, moist air, all 

 exert a decided and appreciable influence on the 

 amount of food which is taken. 



IV. In the foregoing pages, it has been assumed 

 that it is especially carbon and hydrogen which, by 

 combining with oxygen, serve to produce animal 



