1. Henderson and Snell, J. Biol. Chem., 172, 17 (1948). Greenhut, et al., J. Nutrit., 35, 689 (1948); J. Biol. Chem., 162, 69 (1946). Schweigert et al., J. Biol. Chem., 180, 1078 (1950).
2. Symposium on Animal and Vegetable Foods in Nutrition, Brit. J. Nutrit., 5, 243 (1951).
3. Massieu, et al., J. Nutrit., 38, 293 (1949).
4. Riesen, et al., J. Biol. Chem., 167, 147 (1947).
5. Estimated value from the data of Jones, J. Biol. Chem., 122, 751 (1938).