The Discovery of Penicillin

The short analysis

In 1928, Alexander Fleming noticed that a mould contaminating one of his bacterial cultures was killing the surrounding bacteria. He identified the mould as Penicillium and named the antibacterial substance it produced penicillin, publishing his findings the following year. Yet Fleming could not isolate or stabilise the compound, and the observation languished largely unnoticed for over a decade. The story only resumed in earnest when Howard Florey and Ernst Chain, working at Oxford in the late 1930s and early 1940s, took Fleming's published report seriously and attacked the chemical problem with fresh tools. Their team managed to purify penicillin sufficiently to test it in animals, and when the results proved dramatic, they moved quickly toward human trials. The drug's transformation from laboratory curiosity to battlefield medicine was then driven largely by American pharmaceutical industry, whose manufacturing capacity far outstripped anything Britain could offer under wartime conditions. By the end of the Second World War, penicillin was being produced on an industrial scale and saving lives that would previously have been lost to infected wounds and bacterial disease. The episode illustrates a truth that runs through many scientific breakthroughs: observation opens a door, but practical benefit depends on the separate and often harder work of making the observation useful.