THE PROBLEM of blood incompatibility between mother and child in the etiology of mental deficiency has been the object of several studies and of interesting speculations in recent years.
There are two distinct aspects of the problem. The first concerns the question whether mental deficiency may result from the acute brain damage (so-called kernicterus) that is observed during the course of hemolytic disease of the newborn caused by maternal isoimmunization with Rh or AB factors. That this type of mental deficiency does occur occasionally seems now well established, and its clinical and pathological aspects are fairly well known. Some 63 cases of this type from the literature and 16 original observations were recently described by Evans and Polani.1
The second and vaster aspect of the problem concerns the possibility that maternal isoimmunization with blood antigens occasionally produces mental deficiency in the child when no signs of hemolytic disease and/or