Alexander Fleming and the Story of Penicillin

Never one to worry about neatness, Scottish-born scientist Alexander Fleming often grew cultures in unwashed petri dishes. In the hot summer of 1928, Fleming left for a two-week vacation. In his haste, he forgot to clean up an old culture plate that he had smeared with staphylococcus bacteria. Soon after he left, a spore containing a rare strain of a fungus mold called penicillium drifted into his lab from another lab in the same building and settled onto the messy culture plate. Things heated up—and the bacteria on the plate sprouted like a weed—except in the spot where the penicillium spore had settled and grown. Fleming believed he had discovered something very important. Not everyone else agreed. In fact, it would take until World War II, when he was well into middle age, before anyone appreciated his discovery.