‘The shape of the human being as a function of time’: time, transplantation, and tolerance in Peter Brian Medawar's research, 1937–1956

Using tissue transplantation, the British scientist Peter Brian Medawar showed how extrinsic cells could be permanently integrated into an animal's body without provoking immune responses. With his study of this phenomenon—which he called ‘actively acquired tolerance’—Medawar was awarded the Nobel Prize in Medicine and Physiology in 1960 along with the Australian scientist Frank Macfarlane Burnet, who theoretically predicted the possibility. The monumental work of Medawar stems from his long and deep interest in the nature of living organisms’ changes over time, such as growth, aging, and evolution. In particular, his concern for the phenomenon of decline played a critical role in his research design regarding tolerance and its interpretation.