METABOLISM AND FOOD 83 



From the large number of investigations which 

 have been carried out in the last few years, it is 

 possible to learn whether the digestible nutrients 

 of the ordinary feeding-stuffs act in the same way, 

 or differently, to the representatives of the same 

 groups when fed in pure form. Experiments were 

 carried out with the aid of the respiration chamber 

 in exactly the same way as was done with the pure 

 nutrients. A known quantity of the feeding-stuff 

 was added to a basal ration sufficient for mainten- 

 ance, and the digestibility as well as the increase of 

 flesh and fat were determined for the maintenance 

 ration and for the increased ration. In this way 

 it was found what amount of flesh and fat was 

 obtained from the added food-stuff. In the case 

 of various oil-cake meals it was shown that from 

 each kilogram of dry substances consumed the 

 animals digested the following quantities, in grams — 



Cotton-seed Earth-nut Palm-nut Linseed 

 cake meal. meal. cake meal, cake meal. 



If these nutrients had behaved exactly as the 

 pure digestible protein, fat, and carbohydrates,* 

 then there would have been stored in the body of 



* Carbohydrates = nitrogen-free extract + crude fibre. 



