In the early 1920s, the British scientist Alexander Fleming reported that a product in human tears could make bacterial cells dissolve. Rut Fleming’s finding, which he called lysozyme, would prove to be a dead end in the search for an efficacious antibiotic, since it typically destroyed nonpathogenic bacterial cells as well as harmful ones.
Fleming’s second discovery, though, would be one of medicine’s greatest breakthroughs. In 1928 he discovered another antibacterial agent, quite by chance. Returning from a weekend away, Fleming looked through a set of plates on which he had been growing bacteria cultures. On one of them, he found that colonies of the Staphylococcus bacteria had dissolved. He noticed that bacterial cell had disintegrated in an area next to the mould growing on the plate and hypothesized that a product of the mould had caused it. That product was penicillin, the fundamental ingredient of most antibiotics now the standard treatment for infections.
While Fleming generally receives credit for discovering penicillin, he in fact merely rediscovered it. In 1896, the French medical student Ernest Duchesne had discovered the antibiotic properties of Penicillium, but failed to report a connection between the fungus and a substance that had antibacterial properties, and Penicillium was forgotten in the scientific community until Fleming’s rediscovery.
