1 66 FEEDING FARM ANIMALS 



or function of the albuminoid material. The principal al- 

 buminoids of the body are albumen, found in nearly all its 

 fluids, flesh fibrin, the chief constituents of muscular fibre, 

 blood fibrin, the essential element of the clotting part of 

 blood, and casein, the constituent of milk which forms the 

 basis of cheese. The gelatinoids form the nitrogenous sub- 

 stance of the bones and cartilages and also make up the 

 larger part of the tendons, ligaments, connective tissue and 

 the skin. The horny matters, which differ but little in chem- 

 ical composition from the albuminoids or gelatinoids, are 

 found chiefly on the outer surfaces of the body, that is, in 

 the epidermis or scarf skin, the hair, the wool, the horns 

 and the hoofs. The chemical composition of these three 

 groups of nitrogenous substances is practically the same, 

 and what is exceedingly important in this connection, the 

 same chemical composition will hold good with respect to 

 the nitrogenous substances found in foods. The further 

 discussion of the many and exceedingly important functions 

 of the nitrogenous substance in the animal body cannot be 

 carried further in this work. 



The principal non-nitrogenous constituents of feed- 

 ing stuffs are cellulose, starch, sugar, gum, fat, oil and the 

 various vegetable acids. These are classified as carbohy- 

 drates and fat. The carbohydrates, composed principally 

 of carbon, hydrogen and oxygen, include cellulose, starch, 

 sugar, gum and the vegetable acids. The fat and oil are 

 generally considered together as fat. The non-nitrogenous 

 constituents of plants may, therefore, be considered as be- 

 ing carbohydrates or fats. But a part of the cellulose of 

 plants often becomes hardened into a more or less indigesti- 

 ble fibrous condition. This is commonly separated from the 

 remaining carbohydrates in the table of feeding stuffs (see 

 p. 175) and placed in a class by itself as crude fibre. The 

 non-nitrogenous substance also includes the ash, that is, the 

 inorganic or mineral part which remains after the plant has 

 been consumed by fire. These all play a more or less impor- 

 tant part in the economy of animal growth and production. 



