+-----------------+-------------+-------------+-------------+ | | | | | | | Gliadin. | Glutenin. | Leucosin. | | | | | | +-----------------+-------------+-------------+-------------+ | | per cent | per cent | per cent | | Leucin | 5.61 | 5.95 | 11.34 | | Lysin | 0 | 1.92 | 2.75 | | Arginin | 3.16 | 4.72 | 5.94 | | Glutaminic acid | 37.33 | 23.42 | 6.73 | | Ammonia | 5.11 | 4.01 | 1.41 | | Aspartic acid | 0.58 | 0.91 | 3.35 | | Tyrosin | 1.20 | 4.25 | 3.34 | +-----------------+-------------+-------------+-------------+ It is obvious from these figures that the three proteids of the wheat kernel are radically different from each other. Contrast, for example, the content of glutaminic acid in gliadin with the amount in leucosin. With such striking differences in chemical make-up, it is reasonable to assume that corresponding differences in physiological action or food values may exist. Further, “in respect to the amount of these amino-acids, leucosin more nearly resembles the animal proteins than the seed proteins thus far examined, and in this connection it is interesting to note that leucosin occurs chiefly if not wholly in the embryo of this seed and is probably one of its ‘tissue’ proteins, in contrast to the ‘reserve’ proteins of the endosperm of which gliadin and glutenin form the chief part” (Osborne and Clapp). In other words, animal proteids, such as those of meat, are characterized like leucosin by a small content of glutaminic acid and ammonia; while leucin, lysin, aspartic acid, and arginin are relatively more abundant. Until we know more on this subject, however, any broad generalization would be out of place, but certainly there is justification for the supposition that in these differences in chemical constitution are to be found explanation of some of the peculiarities common to certain varieties of proteid food. Wheat flour, aside from its starch, is composed mainly of glutenin and gliadin with their large content of glutaminic acid. Meat proteids, on the other hand, like leucosin, contain only a small fraction of this acid, and, with the other differences indicated, meat proteid and wheat proteid as food for dogs or other high proteid consumers may reasonably be expected to have at the least very unequal values. And if we go a step beyond this and suppose that in the formation of true tissue proteid or the living protoplasm of the cell, certain of these end-products of proteid decomposition are absolutely indispensable, we can easily picture for ourselves a dearth of such building stones in the long-continued use of a diet which lacks that