THE CHEMICAL COMPOSITION OF FEEDINGSTUFFS 19 



of these elements found in the most a]:)midant fats as com- 

 pared mth the percentages found in glucose, a carbohydrate, 

 and with the average percentages found in the simple pro- 

 teins, are as follows : 



On combustion, therefore, the fats are capable of Hberating 

 more energy than the carbohydrates and proteins. Conse- 

 quently fats are of particular importance as a means of 

 storing reserve food. About two and one-quarter times as 

 much energy can be stored in a given amount of fat as in 

 the same amount of carbohydrates. 



Fats are compounds or salts formed by the combination 

 of fatty acids and glycerin. Thus the fat, palmitin, is formed 

 by the combination of glycerin and palmitic acid according 

 to the follo^ving formula : 



r OH r HO.CO.C15H31 r O.CO.C15H31 



CaHs^ 0H+ j HO.CO.Ci5H3i=C3H5J O.CO.C15H31+ 3H2O 

 i OH [ HO.CO.C15H31 [ O.CO.C15H31 



Glycerin 



Palmitic acid 



Palmiti 



A fat which is liquid at ordinary temperatures is known as 

 an oil. The most important animal fats are stearin and 

 valmiiin, which predominate in the more solid fats, as 

 mutton and beef tallow; and olei?i, which predominates in 

 the more hquid fats, as cod hver oil. These fats are also 

 included in many vegetable fats. A great variety of other 



