Following the discovery of the Rhesus factor by Landsteiner and Wiener (1940) and the demonstration by Levine, Burnham, Katzin, and Vogel (1941) that haemolytic disease of the newborn generally is the result of mother-child Rh incompatibility several reports of erythroblastosis foetalis attributable to sensitization of the mother by the A or B foetal antigens have been published, notably those ...