How did Fleming's method lead to penicillin?
My method was largely one of meticulous observation and a willingness to pursue unexpected findings. I kept my laboratory rather untidy, which, as it turned out, was fortunate. When I returned from holiday and saw that a petri dish of Staphylococcus had been contaminated by a mold, most might have simply discarded it. But I was prepared to recognize the unexpected. I observed that the mold inhibited the growth of the bacteria. I then systematically set about isolating the active principle from the mold and testing its effects. This empirical approach, focusing on what could be seen and measured in the laboratory, was crucial. The results were quite remarkable and led to further investigation.
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