What Was That Mold?
Fleming spent several weeks growing more mold and trying to determine the particular substance in the mold that killed the bacteria. After discussing the mold with mycologist (mold expert) C. J. La Touche who had his office below Fleming's, they determined the mold to be a Penicillium mold. Fleming then called the active antibacterial agent in the mold, penicillin.
But where did the mold come from? Most likely, the mold came from La Touche's room downstairs. La Touche had been collecting a large sampling of molds for John Freeman, who was researching asthma, and it is likely that some floated up to Fleming's lab.
Fleming continued to run numerous experiments to determine the effect of the mold on other harmful bacteria. Surprisingly, the mold killed a large number of them. Fleming then ran further tests and found the mold to be non-toxic.
Could this be the "wonder drug"? To Fleming, it was not. Though he saw its potential, Fleming was not a chemist and thus was unable to isolate the active antibacterial element, penicillin, and could not keep the element active long enough to be used in humans. In 1929, Fleming wrote a paper on his findings, which did not garner any scientific interest.
Twelve Years Later
In 1940, the second year of World War II, two scientists at Oxford University were researching promising projects in bacteriology that could possibly be enhanced or continued with chemistry. Australian Howard Florey and German refugee Ernst Chain began working with penicillin. Using new chemical techniques, they were able to produce a brown powder that kept its antibacterial power for longer than a few days. They experimented with the powder and found it to be safe.
Needing the new drug immediately for the war front, mass production started quickly. The availability of penicillin during World War II saved many lives that otherwise would have been lost due to bacterial infections in even minor wounds. Penicillin also treated diphtheria, gangrene, pneumonia, syphilis and tuberculosis.
Though Fleming discovered penicillin, it took Florey and Chain to make it a usable product. Though both Fleming and Florey were knighted in 1944 and all three of them (Fleming, Florey and Chain) were awarded the 1945 Nobel Prize in Physiology or Medicine, Fleming is still credited for discovering penicillin.