THE REQUISITES OF THE DIET 351 



siderably below the older standards of quantity. English 

 critics have expressed surprise that the diets recom- 

 mended have furnished no more protein and no greater 

 fuel-value than the food of the very poor in London or 

 the " punishment ration" of British prisons. We are 

 not disposed to deny the force of this comparison, but 

 we realize much more fully than we did even five years 

 ago that quality as well as quantity must be taken into 

 account in any such discussion. 



We have seen that two rations may be equal in protein, 

 as shown by ordinary analysis, and far from equal in 

 their power to nourish. If the protein in one case is 

 from meat or rice it will determine the superiority of 

 that diet to. one in which the protein is from beans or 

 corn. We now see, in addition, that one ration may 

 satisfy requirements not met by the other because of 

 its minor constituents both mineral and organic. The 

 vitamins must be supposed to arise as by-products of 

 metabolism in the living matter which is destroyed to 

 become our food; they cannot be obtained from proteins 

 by mere digestion. Quite failing to modify the figures 

 that represent quantitative composition, they still confer 

 the most important properties upon foods which contain 

 them. 



