The real story
In September 1928 Alexander Fleming came back from a summer holiday to his lab at St Mary's Hospital in London. Among a stack of staphylococcus plates was one with a blob of mould and a clear ring around it where the bacteria had died. The popular story says the spores floated in through an open window, but colleagues later said his window stayed shut. The likely source was a mould lab on the floor below.
Fleming called his filtered 'mould juice' penicillin and published in 1929, but it was unstable and hard to make. A decade later, Howard Florey and Ernst Chain's team in Oxford purified it and proved it could cure infections. Wartime factories in the US scaled it up in deep tanks, helped by a far more productive mould strain found on a mouldy cantaloupe at a market in Peoria, Illinois. Fleming, Florey and Chain shared the 1945 Nobel Prize.
