is therefore apparenl thai the mosl valuable proteins will I thai 



contain an array of units thai can be reunited t<> form all th< 

 of protein entering into the structure of the bodj pi turally, 



the protein which mosl nearly meets the requirements is meal prot< 

 so thai we are no1 surprised to find thai let than of any other 



protein has to 1"' taken to gain nitrogen equilibrium. 



Tli'- mosl exacl information regarding the d valu< 



proteins has been Becured b} observations on the rate of growth ing 



animals. This method yields more reliable information than ran be 

 Becured by studies on the nitrogenous balance, because it is no1 usually 

 possible to keep up the latter observations for fficient period 



time, or to secure an adequate number of data. Dui a rowth I 

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

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

 ple expedienl of observing the body weight, to dra tlusions 

 the influence of various E Istuffs on tissue construction. 



