Multiple Choice, Multiple Answers

The story of penicillin is often told as a lucky accident. In 1928, Alexander Fleming noticed that a mould growing on one of his culture plates had killed the bacteria around it. Yet Fleming's observation did not lead directly to a medicine. He found the active substance difficult to extract, it seemed to break down quickly, and after publishing his results he moved on to other work. More than a decade passed before a team at Oxford, led by Howard Florey and Ernst Chain, returned to the problem. Their contribution was less a single insight than years of patient laboratory work. They developed methods to purify penicillin, showed in 1940 that it protected infected mice, and then treated the first human patients. Supplies were so scarce at first that penicillin was recovered from patients' urine and reused. Turning a laboratory success into a widely available drug required yet another set of skills. During the Second World War, government agencies and drug companies in the United States worked together on large-scale fermentation, and researchers found a strain of mould, growing on a melon, that produced far more penicillin than Fleming's. By 1944, production was large enough to treat many wounded soldiers. Historians now use the case to show that a discovery and a usable treatment are different achievements, each depending on different people and resources.