The amino-acid minimum for maintenance and growth, as exemplified by further experiments with lysine and tryptophane (Osborne, T. B., and Mendel, L. B. (1916) J. Biol. Chem. 25, 1-12) and The role of vitamines in the diet (Osborne, T. B., and Mendel, L. B. (1917) J. Biol. Chem. 31, 149-163).