Studies in the Synthesis of Hippuric Acid in the Animal. Organism. v. the Influence of Amino-acids and Related Substances on the Synthesis and Rate of Elimination of Hippuric Acid after the Adminis- Tration of Benzoate.*

The problem of the origin of the glycine available for hippuric acid synthesis after the administration of benzoic acid or its salts has been studied by many investigators with varying results. It should be borne in mind, in this connection, that all species of animals do not react similarly in response to the ingestion of benzoic acid. Thus the organisms of man (l), the rabbit (2), the goat (3, 4), and the pig (5, 6) have a store of readily available glycine as evidenced by the fact that they conjugate almost completely sublethal doses of benzoates and eliminate hippuric acid quantitatively. The dog (7), however, after benzoate ingestion, eliminates much free benzoic acid, a considerable amount of benzoic acid in conjugation with glycuronic acid, and less than 50 per cent of the ingested benzoic, in most cases, combined with glycine. Birds (8) eliminate dibenzoyl ornithine after the administration of benzoates and utilize ornithine rather than glycine as the detoxicating agent. The cause of these variations in the chemical mechanism by which benzoic acid is rendered less injurious to the organism is not known. Analyses of the many attempts to discover the source of the glycine used by many species for detoxication of benzoic acid or its