Owing to the difficulty of dealing with substances of high molecular weight we are still a long way from having determined the chemical characteristics and the constitution of proteins, which are regarded as the principal con-stituents of living organisms.

Further because type O blood possesses neither characteristic A nor B the immune systems of persons with blood group AB do not refuse the donation. A number of publications from that period some of them in co-operation with his professors show that he did not restrict himself to hearing lectures. Throughout the 1920s Landsteiner worked on the problems of immunity and allergy.

Wiener the Rhesus factor in 1937 thus enabling physicians to transfuse blood without endangering the patient′s life. In 1930 he received the Nobel Prize in Physiology or Medicine. He was awarded a Lasker Award in 1946 posthumously and is recognised as the father of transfusion medicine.