DOMESTICATED ANIMALS. 83 



food of geese or fowls contains no goose fat or capon 

 fat. The masses of fat found in the bodies of these 

 animals are formed in their organism ; and when the 

 full value of this fact is recognised, it entitles us to con- 

 clude that a certain quantity of oxygen, in some form 

 or other, separates from the constituents of their food ; 

 for without such a separation of oxygen, no fat could 

 possibly be formed from any one of these substances. 



The chemical analysis of the constituents of the food 

 of the graminivora shows, in the clearest manner, that 

 they contain carbon and oxygen in certain proportions ; 

 which, when reduced to equivalents, yield the following 

 series : 



In vegetable fibrine, albumen, and caseine, there are contained, 



for 120 eq. carbon, 36 eq. oxygen 



In starch 120 100 



In cane sugar 120 110 



In gum 120 110 



In sugar of milk (..';. .... 120 120 



In grape sugar 120 140 



Noio in all fatty bodies there are contained, on an 

 average 



for 120 eq. carb. only 10 eq. oxygen. 



Since the carbon of the fatty constituents of the ani- 

 mal body is derived from the food, seeing that there is 

 no other source whence it can be derived, it is obvious, 

 if we suppose fat to be formed from albumen, fibrine, 

 or caseine, that, for every 120 equivalents of carbon 

 deposited as fat, 26 equivalents of oxygen must be sep- 

 arated from the elements of these substances ; and fur- 

 ther, if we conceive fat to be formed from starch, sugar, 

 or sugar of milk, that for the same amount of carbon 



