The Penicillin Story

Sir Alexander Fleming announced his discovery of the mold byproduct penicillin on this day in 1929. Fleming’s scholarly paper only tentatively suggested that penicillin “may be an efficient antiseptic” against some bacteria — his department head at St. Mary’s Hospital, London even wanted this speculation edited out — and his experiments over the following decade arrived at nothing close to a “Eureka!” Unable to move much beyond his initial discovery, and with few other scientists interested in penicillin’s potential, Fleming all but dropped his research on the topic. In 1938 a team of Oxford researchers, led by Howard Florey and Ernst Chain, took interest in Fleming’s 1929 paper; by 1940 they were able to produce penicillin in a pure and stable form, suitable for antibiotic applications; in 1945 Fleming, Florey, and Chain all shared the Nobel Prize for Medicine.

Fleming always tried to dispel the myth, still persistent today, that he discovered one of the century’s most important drugs. Nor did he mind telling, even in his Nobel Lecture, the now-famous story of how his first batch of penicillin resulted from a messy lab, the mold found growing in an unwashed petri dish. In The Mold in Dr. Florey’s Coat, an account of the wider serendipity that surrounds the “Discovery of the Penicillin Miracle,” Eric Lax describes Fleming as a man with “a frolicsome mind” and a talent for “play with microbes”:

Fleming well knew that different bacteria take on different hues as they grow, and he was adept at carefully planting various microbes on a plate of agar — the waxy, gelatinous laboratory food trough for bacteria — so that when they bloomed, the plate turned into a colorful painting of, say, a ballerina in a red skirt or a mother nursing her baby with a bottle.

Lax notes that Fleming became so adept at his microbe art that he displayed it at science conferences — raising eyebrows among those colleagues who felt that “this whimsy lacked the dignity and seriousness appropriate to the high-minded work of science.” But a lot of good science can come from playful creativity, says Lax:

When a visitor to the lab of the Danish physicist Niels Bohr [Nobel, 1922] told him with some disgust, “In your institute nobody takes anything seriously,” Bohr answered, “That’s quite true, and even applies to what you just said.”

Daybook is contributed by Steve King, who teaches in the English Department of Memorial University in St. John’s, Newfoundland. His literary daybook began as a radio series syndicated nationally in Canada. He can be found online at

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