METABOLISM 



595 



Both rats will grow normally in spite of the practical absence of carbohydrates 

 in Diet i. In the case of man, the withdrawal of carbohydrates is followed by 

 acidosis (see p. 609). This acidosis is absent or much less pronounced in the 

 case of the white rat. 



4. Influence of Fat Deficiency. That fats are not essential dietary 

 constituents provided we derive sufficient energy from carbohydrates 

 and proteins and a proper supply of "Fat-soluble A" from some 

 suitable non-fat source is easy of demonstration. 1 



FIG. 1 86. RAT RECEIVING WHEAT PROTEIN ONLY. THIS DIET WAS DEFICIENT IN 



Lysine. COMPARE FIG. 185. 



Demonstration on Fat Deficiency. Place two young white rats (30-60 grams) 

 in individual cages. Feed one the adequate diet listed as Diet i in the following 

 table. Feed the other rat Diet 2, in which alfalfa or spinach is substituted for 

 the butter fat. 



FAT DEFICIENCY DIET 



Both rats will grow normally, indicating that a fat-free diet is satisfactory 

 for growth, provided the diet in question contains ample "Fat-Soluble A" 

 vitamine. Hindhede 2 claims that fat is not an essential dietary constituent 

 provided sufficient fruit and vegetables are eaten to supply vitamines. 



^sborne, Thomas B., and' Mendel, Lafayette B.: Jour. Biol. Chem., 45, 145, 1920. 

 2 Hindhede: Skand. Arch. Physiol., 39, 78, 1920. 



