STARVATION 573 



is therefore apparent that the most valuable proteins will be those that 

 contain an array of units that can be reunited to form all the varieties 

 of protein entering into the structure of the body proteins. Naturally, 

 the protein which most nearly meets the requirements is meat protein, 

 so that we are not surprised to find that less of this than of any other 

 protein has to be taken to gain nitrogen equilibrium. 



The most exact information regarding the "food value" of different 

 proteins has been secured by observations on the rate of growth of young 

 animals. This method yields more reliable information than can be 

 secured by studies on the nitrogenous balance, because it is not usually 

 possible to keep up the latter observations for a sufficient period of 

 time, or to secure an adequate number of data. During growth the 

 building-up processes are in excess of the breaking-down, so that the 

 effect is an increase in bulk of the tissues, thus permitting us, by the sim- 

 ple expedient of observing the body weight, to draw conclusions as to 

 the influence of various foodstuffs on tissue construction. 



