Florey studied medicine at Adelaide and Oxford universities until 1924. After holding teaching and research posts at Cambridge and Sheffield universities, he was professor of pathology at Oxford (1935–62). He was appointed provost of Queen's College, Oxford (1962), and chancellor of the Australian National University, Canberra (1965), positions he held until his death. He also served as president of the Royal Society (1960–65). He was knighted in 1944 and made life peer, assuming his title as baron, in 1965. Florey investigated tissue inflammation and secretion of mucous membranes. He succeeded in purifying lysozyme, a bacteria-destroying enzyme found in tears and saliva, and characterized the substances acted upon by the enzyme. In 1939 he surveyed other naturally occurring antibacterial substances, concentrating on penicillin. With Chain and others, he demonstrated its curative properties in human studies and developed methods for its production. Following World War II and the work of his research team in North Africa, penicillin came into widespread clinical use.