Uses of Mineral Compounds — Protein 153 



them in order to sustain the nutritive functions. It is 

 especiallj' true of milch cows, which store combinations 

 of phosphoric acid, lime and potash so abundantly in 

 the milk that they must have an adequate supply of 

 these substances. Nothing is clearer than that these 

 materials must of necessity be furnished in the food. 

 They cannot originate in the animal, neither can car- 

 bon compounds take their place. 



Nature seems to have made generous provision 

 for the animals' needs along this line. All of our 

 home -raised feeding stuffs, as usuallj^ fed, contain in 

 variety and quantity all that is needful of these nu- 

 trients except for poultry perhaps. Milk, that is the 

 exclusive food of very young animals, is especially cal- 

 culated to sustain the rapid bone formation which is 

 taking place. It is only when feeding is one-sided, as 

 in an exclusive corn diet, or when parts of a grain are 

 removed, that we need fear a deficiency of the neces- 

 sary mineral compounds. 



FUNCTIONS OF PROTEIN 



While there are at present many unsolved problems 

 relative to the nutritive offices of protein, there is no 

 reasonable doubt that tlie vegetable proteids are the 

 only sources of similar substances in the animal body. 

 This is equivalent to a statement that from the pro- 

 teids are formed the muscles, the connective tissues, 

 the skin, hair, horn, and hoofs, and the major part of 

 the tissues of the secretive and excretive organs; in 

 short, that they are the source of a large proportion 



