Biological Values of Wheat and Almond Nitrogen

The attempt to compare the biological values of various protein foods, made by Karl Thomas (1) in 1909, has resulted in a good deal of discussion, but few confirming experiments. The brevity of his nitrogen balance periods, as well as the arbitrary formulas used by him in the calculation of the percentage efficiencies reported, are the basis of criticism made recently by American authors (2, 3). The comparison of qimal quantities of food nitrogen which suffice to maintain equilib. “11 in the adult body may, however, be accepted as indicating to some degree the relive protein values of those foods. The application of data obbamed in this way may need to be carried out with caution nevertheless, since as McCollum, Simmonds, and Parsons (4) have pointed out, the nitrogen metabolism in the adult body may differ in some respects from that observed during the growth of the young, or during the process of lactation.