AUTHOR S PREFACE Vll 



present time, no one denies the feasibility of maintaining either 

 man or animals in a condition of nitrogenous equilibrium on 

 quantities of protein very much below the standards set up by 

 the old 'masters in the science of nutrition. 



If we knew exactly how much, and what particular nitrogen 

 compounds the body requires in each specific state of nutrition, 

 it is rational to expect that it would be possible to maintain the 

 body in health, vigour, and efficiency on quantities of protein 

 very much less than those hitherto considered necessary ; but, 

 as we do not know what form of nitrogen combination nor how 

 much of any particular unit is required in the different states of 

 bodily nutrition, it is surely only rational that, in order to insure 

 a sufficiency of those elements absolutely essential, a liberal 

 standard of dietary should be recommended. The work of Leonard 

 Hill and Flack on flours, and the researches carried out on the 

 production of beri-beri by feeding animals on rice deprived of 

 certain of its outer layers, show how important certain minute 

 constituents of the food may be. 



It seems, therefore, only reasonable to lay down such a 

 standard of protein in the feeding of man as will at least give 

 to the body the opportunity of obtaining the particular com- 

 binations it requires in any given state of nutrition. 



This deduction is fully borne out by a careful consideration 

 of the information available from dietary studies carried out 

 in many different countries, and particularly by the investiga- 

 tions made in India to determine the effects of different degrees 

 of protein interchange on several tribes and races living under 

 exactly the same conditions, except as regards diet. An abso- 

 lutely dispassionate survey of the physical development and 

 general capabilities of the races and people of India points 

 undoubtedly to the conclusion that, other factors being elimin- 

 ated, those who obtain a liberal supply of absorbable protein 

 in their daily food are superior in every respect to those whose 

 dietaries exhibit any marked degree of lowering of the average 

 protein standard. 



The general conclusion arrived at, from a broad consideration 

 of all the facts available in the present state of our knowledge, 

 is that the views held by the older writers on nutrition are 

 sounder and more in accord with the findings of careful scientific 



