Studies on the Metabolism of Arginine and Histidine

IN the first paper of this series [Stewart, 1925] it was reported that liver perfusion experiments had failed to afford any evidence in support of the suggestion, advanced by Ackroyd and Hopkins [1916], that arginine and histidine are utilised in the animal body as precursors of purines. As was there pointed out, however, the evidence derived from the perfusions, while unable to confirm the hypothesis, was equally unable to invalidate it, and so did nothing to remove the uncertainty as to the function of arginine and histidine which has been produced by the contradictory results of subsequent workers.