IT has been previously reported from this laboratory that both animal (rat)1,2 and human3 red blood cell hæmolysates show the presence of minor protein components other than hæmoglobin after electrophoresis in agar gel medium. Because of their possible interaction with hæmoglobin molecules in the red cell and their variation in hæmatological disorders and other pathological conditions, more detailed study of these proteins appeared of interest.