ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 261 



Each of these substances differs a little from these quantities 

 which are freed from fractions and given in even numbers. Such 

 is the composition of animals, and as has been stated, the food 

 must necessarily contain similar elements or it cannot contribute 

 to the healthful nutrition of the animal body. 



Hence, the skillful feeder will not only change the food from 

 time to time, but also to vary the properties, he will adapt the 

 kind and quantity of food to the age of the animal, according to 

 the purposes for which it is fed. The young animal requires 

 especially, food rich in nitrogen, or, more properly, the protein 

 compounds, which contain nitrogen. To show the close identity 

 of these, both in animal and vegetable life, the three tables of 

 albumen, fibrin and casein will serve. Albumen is the chief 

 constituent of the eggs of fowls, and of the milk of animals. 

 Fibrin is the principal element of the muscles of animals, and it 

 forms the clot and globules of the blood. Casein is also a con- 

 stituent of milk. It is identical with the legumen of beans, peas 

 and the seeds of all other leguminous plants. 



ALBUMEN. 



Name. Animal. Vegetatble. 



Carbon 53.5 53.7 



Hydrogen 7.1 7.1 



Oxygen 23.6 23.5 



Nitrogen 15.8 15.7 



100.0 



FIBRIN. 



Name. Animal. 



Carbon 52.8 



Hydrogen 7.0 



Oxygen 23.7 



Nitrogen 16.5 



1 00.0 



Vegetable. 



53-2 

 7.0 



2 34 

 16.4 



100.0 



100.0 



