The high mortality in erythroblastosis fetalis and the dramatic nature of replacement transfusions have attracted wide attention among both the medical profession and the laity. However, the final value of replacement transfusions has not been completely established. Diamond,1 in a recent communication, indicated that he was still somewhat hesitant about drawing conclusions from his data, which at that time covered fifteen months of experience and 95 infants personally treated by replacement transfusions. The high death rate before the advent of exchange transfusions (approximately 30 per cent) makes it difficult to deny an erythroblastotic infant a form of therapy claimed to give promising results. On the other hand, it is well known that some infants with this condition and appearing to offer a poor prognosis do recover under what one might term "conservative therapy." The latter comprises repeated small transfusions of suitable Rh-negative blood, in an effort to maintain a