One of two imitation culture plates of penicillium mould, c. 1963
This is a replica of the culture plate on which penicillin was discovered. In 1928 Alexander Fleming (1881-1995), a British bacteriologist, observed that a stray growth of Penicillium mould could affect colonies of bacteria. Around the felt-like greenish mould he noticed a sterile area where the growth of bacteria had been stopped by Penicillium. However, penicillin’s nature and potential use as an antibiotic were not immediately obvious to him and so it was not isolated or developed commercially until the early 1940s.