ADEQUACY OF THE ESSENTIAL AMINO ACIDS FOR GROWTH OF THE RAT.

Growth was obtained in rats on synthetic diets in which the ten essential amino acids were the sole source of amino acid nitrogen. The growth rate was dependent upon the quantity of amino acids fed and appeared to compare favorably with that obtained when a similar quantity of nitrogen was fed in the form of casein. No increase in growth was observed when nitrogen in addition to that given in the form of the essential amino acids was supplied as glycine. Our experiments would not support the contention that the unnatural forms of the amino acids are toxic. We wish to acknowledge and thank Phyllis Robison for technical assistance, and Dr. D. Mark Hegsted for helpful suggestions.