8 BULLETIN 717, U. S. DEPARTMENT OF AGRICULTURE. 
same amountof lysine as gliadin. However, the amount of these cereal 
proteins in some of the cereals is insufficient to supply adequate 
amounts of the essential amino acids, whereas soy beans and peanuts 
are rich in glycinin and arachin which yield a high percentage of 
lysine. In considering the dietary value of glycinin and arachin, 
from the standpoint of lysine and tryptophane, the consensus of 
opinion of biochemists seems to be well summed up in the conclusions 
of Osborne and Mendel? who state ‘‘ We have shown that growth does 
not occur when lysine is lacking from the diet but takes place 
promptly on adding this amino acid to the otherwise adequate food,” 
and in the conclusions expressed by Abderhalden,? who says that 
tryptophane is an indispensable component in the dietary. 
It may also be noted, in discussing the relative nutritive value of 
proteins as regards the presence or absence of lysine and tryptophane, 
that Osborne and Mendel? state that lysine must be present in the 
diet since ‘‘the animal organism apparently can not synthesize 
lysine.’”’ These authors ‘ also state that ‘‘Tryptophane can not be 
synthesized by the animal cells.” Accordingly, a theoretical con- 
sideration of the relative nutritive value of soy-bean and peanut pro- 
teins, based upon their amino-acid content alone would indicate that 
glycinin and arachin possessed a greater dietary value than the prin- 
cipal proteins supplied by the common cereals. 
BIOLOGIC VALUE OF SOY-BEAN AND PEANUT PROTEINS AS COMPARED 
WITH THAT OF COMMON CEREAL PROTEINS. 
Feeding experiments have been made by a number of investigators 
for the purpose of securing data regarding the relative biological 
value of proteins supplied by some of the cereals referred to above. 
Willcock and Hopkins ® state that ‘‘loss of weight begins the moment 
it [zein] forms the sole nitrogenous supply.”” Osborne and Mendel ® 
report ‘‘We have now accumulated the results of a large experience 
in feeding zein, with the uniform consequence of decline when this 
protein forms the sole nitrogenous component of the dietary.” These 
results have been confirmed by Wheeler’ in studies with rats and 
later by Hart and McCollum,’ who report that young pigs can not 
grow when the maize kernel is the sole source of nutriment. Hogan ° 
conducted experiments to determine the value of corn protein, zein, 
when fed as the sole source of protein, and concluded that trypto- 
1 Jour. Biol. Chem., 25 (1916), No. 1, p. 2, figs. 4. 
2 Hoppe-Seyler’s Ztschr. Physiol. Chem., 96 (1915), No. 1-2, pp. 1-147. 
3 Jour. Biol. Chem., 17 (1914), No. 3, p. 334. 
‘Ibid., p. 328. 
5 Jour. Physiol., 36 (1906), No. 1-2, p. 100. 
6 Jour. Biol. Chem., 17 (1914), No. 3, p. 338. 
7 Jour. Expt. Zool., 15 (1913), No. 2, pp. 209-223. 
8 Jour. Biol. Chem., 19 (1914), No. 3, pp. 373-395, pls. 2, figs. 11. 
9 Jour. Biol, Chem., 29 (1917), No. 3, pp. 485-493, figs. 3. 
