72 SCIENTIFIC FEEDING OF ANIMALS 



entirely free from nitrogen, and during the experi- 

 ment gained ( + ) or lost ( - ) the following weights 

 of body substance 



I. 



Method of Loss of 



Feeding. Flesh. Fat. 



Fasting .... - 10-1 gr. - 60-5 gr. 



200 gr. bacon . . . - 10-1 gr. +128-2 gr. 



II. 



Fasting . . . - 11-2 gr. 427 gr. 



17-0 gr. sugar ... - 8-5 gr. - 35-8 gr. 



III. 



Fasting .... - 15-8 gr. -25ogr. 

 94 gr. sugar -f 68 gr. starch 



+47 gr. fat . . . - 7-4 gr. +58-2 gr. 



Thus feeding with a ration composed only of 

 nitrogen-free material decreases the metabolism 

 of body protein and body fat. Such nitrogen- 

 free nutrients preserve then the proteins and fats. 

 If along with the nitrogen-free substances proteins 

 are also fed, the protein metabolism regulates itself 

 according to the supply of protein in the food, as 

 was previously seen (p. 62). Under the influence 

 of nitrogen-free substances a slightly smaller quan- 

 tity of protein is metabolised than without. A 

 dog of about 35 kilos (77 Ibs.) weight was fed accord- 

 ing to the following table, with the results recorded 

 below 



