CHAPTER VI. 



ANIMAL NUTRITION. 



The Constituents of the Animal Body. — Water, albuminoids, gelatin- 

 olds, horny matter, fat, and ash constituents — Composition cf 

 animals in various stages of growth and fattening — Composition 

 of wool and milk— loss to a farm by sale of milk, cheese, and 

 butter — Proportion of carcase in different animals— Composition 

 of increase whilst fattening. The Processes of Nutrition. — The 

 constituents of food, their particular functions in the body and 

 relative values — Digestion — Respiration — Excretion. 



In order to understand the mode in which animals 

 are nourished we must first obtain some acquaintance 

 with the nature of the animal body and of the pro- 

 cesses which occur in it. 



The Constituents of Animals. — The elements com- 

 posing the animal frame are the ten already named as 

 forming the essential constituents of plants (pp. 2, 3), 

 with sodium and chlorine in addition. The two last- 

 named elements are commonly present in the suc- 

 culent parts of plants, but are apparently not essential 

 to plant life ; in the animal frame they are, however, 

 indispensable. Fluorine and silicon are also always 

 found in the animal body, but are not known to be 

 essential for life or growth ; fluorine occurs in small 

 quantities in the teeth and bones, and silicon in hair, 

 wool, and feathers. 



The combustible matte?' of the animal body is mainly 

 composed of nitrogenous substances, and of at. 



