UTILIZATION OF FOOD 



413 



means a gain of 3.17 grams of carbon in dry flesh, and a gain of 

 26 grams of moist flesh or muscular tissue. 



The Carbon Balance. Carbon enters the animal in food and 

 water, and leaves it in urine, solid excrement, perspiration, and 

 as the gaseous bodies-carbon dioxide and marsh gas. The marsh 

 gas and part of the carbon dioxide comes from the fermentation 

 in the intestines, but most of the carbon dioxide comes from 

 oxidation of carbonaceous bodies in the animal. For example, 

 the air inhaled and expired by a horse was found to have 

 approximately the following percentage composition : 



The following table gives an example of the determination of 

 the carbon and the nitrogen balance : 



CARBON AND NITROGEN BALANCE. 1 



The gain of 7.23 grams of nitrogen means a gain of 7.23 times 

 6 equals 43.4 grams of dry flesh, containing 22.8 grams of carbon. 

 1 Kellner, Landw. Versuchs-stat., 1900, p. 4. 



