Working half a world apart, these two men made a highly significant contribution to immunology. Although Burnet developed the theoretical foundation of immunology, Medawar succeeded in proving it.

Born in Traralgon, a country town in Victoria, Australia, MacFarlane Burnet attended Geelong College, Victoria, and earned his medical degree from Melbourne University in 1923. He received his Ph.D. from the University of London in 1927. Burnet was associated with Melbourne Hospital for his entire career and also directed the University of Melbourne's Walter and Eliza Hall Institute for Medical Research. He conducted research on immunology throughout his career, even after retirement, and wrote scientific books for the general public.

On his return to Australia from England in 1928, Burnet investigated the deaths of twelve children following diphtheria vaccination. He found that the vaccine had been contaminated by staphylococcus bacteria. This focused Burnet's interest on the ways in which the body defends...