Abstract
SUMMARY: Administration of cortisone in large dosage (20 mg daily) decreases the chances of survival of thyroid autotransplants in guinea-pigs. Despite this, cortisone may facilitate the survival of thyroid homotransplants, apparently by inhibiting the development of resistance in the host. The effect is a slight one, however, and is not apparent when transplants are made from stock donors to members of a highly inbred strain. Administration of thyrotrophin does not abolish the deleterious effect of cortisone on autotransplants, nor does it appear to facilitate the survival of homotransplants.