344 THE CHEMISTRY OF CREATION. 



chief fuel consumed is the carbon and hydrogen 

 contained in the materials of the blood; and 

 therefore derived indirectly, or immediately, as 

 the case may be, from the food. Calculations 

 have been made as to the actual amount of fuel 

 necessary to keep up the temperature of the 

 human body for one day, and it appears, that 

 of all economical furnaces the animal frame is 

 that which evolves the most heat from the same 

 amount of fuel ; for an adult healthy man only 

 consumes for the purposes of respiration about 

 fourteen ounces of fuel-carbon every day ! * A 

 large quantity of hydrogen also is consumed in 

 respiration, and produces a notable amount of 

 that sum of heat, which, with the thermometer 

 at ' Temperate,' is required to keep the body 

 at 96 or 97 for one day. 



The function of respiration, therefore, alone 

 makes large demands upon the body for fuel. 

 Man supplies this, together with the other 

 demands for his nutrition, &c., by the food he 

 consumes. A large part of the food is fuel. 

 Just as in winter we find it necessary to heap 

 up our fires, and thereby to increase the con- 

 sumption of fuel in order to keep up the tem- 

 perature of our dwelling-houses to an agree- 

 able point, so with man. In proportion to the 



* No artificial furnace whatever can compare with these 

 animal furnaces, for the most economical consumes, according 

 to Baron Liebig, not less than from ten to twenty times this 

 amount of fuel in producing the same amount of heat. 



