“…There is considerable evidence in the earlier literature that insulin may cause some inhibition in the growth of malignant tissue (Piccaluga and Cioffari, 1925;von Witzleben, 1925;Silberstein et al, 1927;Gomes da Costa, 1931).t The results of experiments carried out in this laboratory are in general agreement with these earlier reports. We find that, although the effects of giving insulin to rats bearing the Walker carcino-sarcoma vary considerably, a small but significant inhibition of the growth of this tumour is produced in most instances.…”