74 SCIENTIFIC FEEDING OF ANIMALS 



upon its reserve of protein when 0-4-0-6 lb. of 

 digestible protein per 1000 lbs. body weight are 

 given. Equally low figures would also be found 

 in the case of men accustomed to a purely vege- 

 table diet. 



The protective action of the nitrogen-free nu- 

 trients extends, as has been seen, not only to the 

 protein of the body, but also to that of the food. 

 If an animal has the power of turning large quanti- 

 ties of protein into flesh, it is not necessary to feed 

 with a lot of food rich in protein, for a small 

 quantity suffices provided a sufficient supply of 

 nitrogen - free substances is given. The latter, 

 then, play a very important part in the formation 

 of flesh. 



(e) Formation of body fat from food fat. 



The first investigations as to whether the fat of 

 the food can be stored in the body were performed 

 with a dog which, after fasting for thirty days, de- 

 creased in weight from 26-5 to 16-0 kilos. In this 

 state it was computed from other experiments 

 that the body did not contain more than 150 gr. fat. 

 The animal was then given, for five days, a large 

 quantity of fat, the average daily amount being 

 370-8 gr. and 49 gr. dry flesh. At the end of the 

 experiment the animal was killed and the body 

 was found to contain 1352-7 gr. fat, from which 

 the 150 gr. present at the beginning must be de- 



