H A AND B TITRES IN SOUTH AFRICAN BLOOD DONORS

Summary. It is known that the red cells of Bantu of group O have far higher H titres than those of Europeans, and that the cells of A1–A2 intermediates have more H than those of A2 subjects. This latter finding is not in accord with the theory of Morgan and Watkins according to which H substance is the basic material out of which A and B substances are elaborated. To test the theory further, A, B and H red cell titres were compared in Bantu and Europeans of groups A1 and B. Bantu cells of group B have considerably more B substance than those of Europeans; H titres of group B cells are about the same in the two races. Bantu A1 cells, on the other hand, have far more H than A1 cells from Europeans; the A titres are equal in the two races. Both these findings support the Morgan‐Watkins theory. © 1968 Blackwell Publishing Ltd