marendesk

September 28 is the date usually pinned on the discovery. In 1928 it is the day Alexander Fleming confirmed what a contaminated dish had shown him: a stray Penicillium mold killing the staphylococci around it, a clear ring where the bacteria should have grown.

The famous part is the accident. A plate left on a bench before a holiday; a mold later traced to the room below his; the two words everyone quotes, “That's funny.”

The truer part is that he did not shrug. He grew the mold in pure culture, tested it against other bacteria, named the substance penicillin in March 1929, and published. Then almost nobody cared. For most of a decade penicillin sat in a lab while Fleming kept the original mold alive for twelve years and kept asking chemists to help him make enough of it.

It took Oxford, Florey and Chain and Heatley, another war, and 1940 to turn a dish into a drug. Fleming shared the 1945 Nobel for it.

He also warned, before anyone wanted to hear it, that too little would breed resistance. “The thoughtless person playing with penicillin,” he said, “is morally responsible for the death of the man who finally succumbs.”

Ninety-eight years on, the mold still holds the line.