Fleming Discovers Penicillin
Alexander Fleming returned from holiday in September 1928 to a laboratory bench he had not cleared, and found a culture plate of staphylococcus with a mould growing on it and a clear ring around the mould where the bacteria had dissolved. The mould was Penicillium notatum, and it had almost certainly blown up the stairwell from a mycology laboratory on the floor below. The cool August that year is part of the explanation: the mould grew first at low temperature, and the bacteria only afterwards when it warmed. He identified the active substance, named it penicillin, published in 1929, and could not purify it in useful quantity. It was unstable, present in tiny concentrations, and he was not a chemist. He kept the strain alive and largely let the work go. Howard Florey and Ernst Chain at Oxford picked the paper up in 1938 as a piece of pure biochemistry. Chain and Norman Heatley worked out how to extract and stabilise it, growing it in bedpans and biscuit tins. The mouse experiment of May 1940 settled it: eight mice given a lethal dose of streptococci, four given penicillin, and the four untreated dead by morning. The first patient, a policeman with a septic scratch, recovered and then died when the supply ran out — some of it recovered from his own urine. Britain had no capacity to manufacture it in wartime, and Florey took it to America in 1941. Deep-tank fermentation supplied 2.3 million doses by D-Day. Fleming, Florey and Chain shared the Nobel Prize in 1945, and Fleming used his lecture to warn that underdosing would breed resistance.
- Year: 1928 CE
- Category: Scientific
