396 CARNEGIE INSTITUTION OF WASHINGTON. 



It thus appears that protein substances contain practically two- 

 thirds of the nitrogen in each case. While these figures must be 

 accepted as only roughly approximate, we believe they afford a better 

 basis for assuming that the greater part of the nitrogen of the leaf 

 actually belongs to protein substances than has heretofore been 

 presented. 



By applying the results of this investigation to spinach leaves, we 

 have made a protein concentrate which we are now feeding to albino 

 rats. These experiments already indicate that the spinach-leaf pro- 

 teins, for example, are adequate to supply the nitrogenous needs of an 

 animal during the entire period of growth. This fact, coupled with 

 the demonstration that the leaves are comparatively rich in protein 

 material, emphasizes in a new way the importance of the green fodders 

 as sources of nutriment, particularly when it is recalled that they are 

 rich also in water-soluble and fat-soluble vitamines. Similar products 

 are now being made from other green leaves. 



Du'ect chemical evidence has never been obtained that the ammonia, 

 which proteins yield when hydrolyzed arises from an amide combi- 

 nation with one of the carboxyl groups of the dibasic glutaminic and 

 aspartic acids. If this assumption, which has generally been accepted 

 as probably the case, is correct, carboxyl groups should be liberated by 

 hydrolysis in a proportion corresponding to the amount of ammonia 

 produced. By a recently completed study we have shown this to be 

 true ; consequently there is now little doubt that the ammonia nitrogen 

 is present in the protein in the grouping R-CONH2. 



One object of this work was to learn how to make a protein prepara- 

 tion free from amide nitrogen, so that it could be fed to animals under 

 conditions which would determine whether or not this nitrogen has 

 any value in nutrition. As a result of our investigation we now hope 

 to be able to succeed in doing this. In connection with this work it 

 was necessary to study the early stages of hydrolysis of two proteins, 

 gliadin and edestin, which represent types of markedly different chemi- 

 cal constitution. It is possible that what we have thus learned may 

 help to gain a further insight into the structure of the protein molecule. 



Fresh fruits have long been used for the prevention of scurvy, yet 

 almost no experimental data have been available with respect to the 

 distribution of the vitamines in them. We have, therefore, under- 

 taken a series of experiments to test the possible presence of water- 

 soluble vitamine in some of the more common fruits. The fresh 

 juices of the orange, lemon, and grapefruit have been found to con- 

 tain water-soluble (B) vitamine. Their potency in this respect is 

 quite similar to that of comparable volumes of cow's milk. The effi- 

 ciency of these fruit juices is not lost by suitable modes of desiccation. 

 A sample of grape juice tested was less potent than equal volumes of 

 the fruit juices just mentioned. The edible portions of apples and 



