Discovery of penicillin

The discovery of penicillin took place in London in September 1928, when the Scottish scientist Alexander Fleming returned to his laboratory at St Mary’s Hospital after a summer holiday and found that something in it had been working harder than he had.^[1]

Before leaving, Fleming had stacked up dishes of bacteria. On one of them a mould had grown, and the bacteria around it had disappeared. It is the most celebrated example in history of not doing the washing-up before going away.

Naming

Fleming at first called the substance “mould juice”. A few months later he renamed it penicillin, after the mould Penicillium, a decision widely regarded as the right one.^[2] He published his findings in 1929.

From dish to medicine

Penicillin then waited about a decade, because nobody could make enough of it to be useful. In the late 1930s and early 1940s a team at the University of Oxford led by Howard Florey and Ernst Chain worked out how to purify it. For a time the team grew the mould in anything that would hold liquid, including bedpans, milk churns and baths, making it the only major medical advance to have been brewed partly in bathroom fittings.^[3]

Large-scale production followed during the 1940s. In 1945 Fleming, Florey and Chain shared the Nobel Prize in Physiology or Medicine. The mould was not nominated.

Penicillin went on to treat bacterial infections that had previously been very dangerous, and has saved a great many lives.

See also

• University of Oxford – where someone worked out how to make more
• Bath – briefly laboratory equipment
• Honey fungus – another fungus, less helpful

References

1. Petri, D. (2003). Back From Holiday. Culture Press.
2. Mould, M. (1999). “Juice: A Working Title”. Journal of Names Tried First 1: 1.
3. Churn, M. (2017). Anything That Holds Liquid. Washing-Up Books.