The transplantation of both autogenous and homogenous grafts has long occupied the efforts of many workers. Williamson reported specifically on renal homotransplantation in 19231 and again in 1926.2 Although the renal transplant has never before been attempted in the human, the fate of homogenous grafts in laboratory animals is fairly well known. Markowitz3 in his discussion of the transplantation of organs presents certain conclusions which show that the greater the similarity of host and donor the more successful is the grafting. Fleisher4 has shown that the lens of the eye is readily transplantable (by implantation) and that it does not become invaded by phagocytes. Mann, Markowitz and associates5 have shown in homotransplants of the intact mammalian heart that the organ will function for as long as eight days but that the muscle finally becomes riddled with phagocytes and ceases to function. According to these workers,