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Image of the week: penicillin production, 20th century


The above image shows equipment (glass flasks and milk churns) used for making early forms of penicillin.

Though Alexander Fleming is credited with having discovered the antibiotic properties of penicillin in 1928, the drug wasn't widely available for another 15 years because of the challenges scientists faced in mass producing it. According to a 1944 Time article, the big obstacle was making the mold that produces penicillin yield more heavily:

This delicate process has more hazards than an obstacle race. The penicillium mold, found in fertile soil, is cultivated in a sugary solution. It develops a network of very fine branches, *called "mycelium," which secrete penicillin. If the delicate mycelium breaks, production of penicillin stops. Temperature must be kept at 24°C. Worst of all hazards is contamination. The sugary bath in which the mold grows is an ideal medium for bacteria; if any get in, they destroy all penicillin present in three hours. And when all these hazards are survived, the yield is fantastically small. The broth from which powdered penicillin is extracted contains only two to six thousandths of 1% of pure penicillin.

The United States, near the end of World War II, dedicated serious effort to mass production. Researchers developed heavier-yielding strains of mold, found that lactose from skimmed milk and corn liquor speeded growth, and worked out a method for making penicillin in tanks rather than flasks.

According to an Annals of Internal Medicine article, first use of penicillin in the U.S. occurred in 1942, when only a tiny quantity of the antibiotic was available. By 1943, 400 million units had been produced; and by August 1945, 650 billion units were distributed each month.

This image is No. 7 of 8 in a series showing the evolution of medical instruments over time. The images are presented in collaboration with the London-based Wellcome Trust, whose library features visual collections with themes ranging from medical and social history to contemporary healthcare and biomedical science.

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