36 THE STOCKFEEDER'S COMPANION 



hair, horns, wool, feathers in fact all those parts of 

 the body containing nitrogen. Further, they are 

 absolutely necessary to sustain life. 



None of the other nutrient constituents, except 

 under certain circumstances the amides, have the 

 power of supplying nitrogenous tissue to the body. 



The albuminoids, like the fat, are temporarily split 

 up by ferments (enzymes) during digestion and absorp- 

 tion into simpler bodies albumoses, peptones, and 

 finally, amino-acids and these amino-acids are again 

 built up into animal albuminoids after or during 

 absorption into the blood. This accounts for the 

 different character of albuminoids in the animal body 

 as compared with those in the food from which they 

 are derived. 



When the albuminoids in food are insufficient to meet 

 the constant waste of nitrogenous tissue in the animal 

 body, the deficiency must be supplied from the flesh 

 which the animal has previously stored up at the time 

 it was receiving a liberal amount of albuminoids ; the 

 animal then begins to lose flesh. Young animals 

 require a more liberal allowance of albuminoids than 

 older ones, inasmuch as they have to support the 

 constant growth in the size of the body in addition 

 to supplying the ordinary waste of tissue. 



Albuminoids may also supply heat and energy 

 when the carbohydrates and fat are not present in 

 sufficient quantities. In this case, the carbon and 

 hydrogen are oxidised in the same way as carbo- 

 hydrates and fat. The nitrogen, however, is not 

 oxidised in the body, but is excreted in the urine. 

 The albuminoids may also be converted into fat ; hence 

 we have seen that the albuminoids have the unique 

 property of forming nitrogenous tissue (flesh) and 



