Which researcher duplicated Fleming's original penicillin result in 1966?

Ronald Hare duplicated Fleming’s original penicillin result in 1966.

For decades, researchers struggled to reproduce Alexander Fleming’s famous observation: a Penicillium mould colony inhibited nearby Staphylococcus bacteria. In 1964, Hare revisited the problem and carefully reconstructed the arrangement shown in Fleming’s original paper and photographs.

On 1 August 1966, he finally reproduced the result. The success was initially difficult to repeat, however, and a second attempt two weeks later failed. Hare suspected temperature was the crucial variable. His experiments showed that the mould and staphylococci behaved in the required way below about 68°F, while temperatures above 90°F prevented the same interaction.

Hare then examined weather records from 1928. He found that Fleming’s original experiment coincided with a heat wave followed by nine cool days beginning on 28 August. The episode illustrates that Fleming’s discovery depended not only on chance contamination, but also on a particularly favorable combination of temperature, microbial growth and experimental layout.