212 



FEEDING 



Protein. Protein is the chief element in all living tissues. 

 Common examples of it, as seen in the bird's body, are lean 

 meat, gristle, feathers, etc. A common example, as seen 

 in the product of the bird's body, is the white of the egg, or 

 albumen. It is complex in its nature, consisting of nitrogen, 



oxygen, hydrogen, carbon, and 

 sulfur. It is characteristic 

 because of the large amount of 

 nitrogen which it contains, this 

 being about fifteen per cent. 

 No nitrogen is found in either 

 of the other three groups here 

 classified. The body of the 

 average bird contains approxi- 

 mately 22 per cent of protein. 

 Fat. As an example of fatty 

 tissue, we have the yellow fat 

 in the abdominal parts of a hen. 

 Fatty tissue consists of minute 

 cells, surrounded by a tough 

 cell wall. The oil or liquid in 

 the center of this wall is the fat. 

 Fat is in reality stored up oil, 

 or a reserved feed supply. 

 Should the bird become short 

 of feed, it would draw upon this 

 fat and use it to nourish the 

 body. In the body of the aver- 

 FIO. 121. Diagram showing the ap- age bird, there is from 15 to 20 



proximate composition of the biro^s f r . j u 



body. Note the large amounts of water P er Cent OI iat, and mUCIl more 



and protein. ,, ,, . ^^ e i 



than this in old fowls, capons, 



and roasting chickens which are especially fattened for market. 



Ash. Ash is a true mineral matter. As the name implies 



it is the material which would be left if the bird's carcass 



were burned by fire. The ash in the body is in the skeleton 



