Alexander Fleming, Scottish bacteriologist, 18 December 1943.

UNITED KINGDOM - FEBRUARY 23: Alexander Fleming, Scottish bacteriologist, 18 December 1943. Professor Alexander Fleming (1881-1955) at work in his laboratory, taken by James Jarche for ‘Illustrated’ magazine. Fleming looks through a microscope as he sits at a desk cluttered with petrie dishes, bottles and test tubes. A can of Lyons' coffee acts as a handy test tube holder. Working as a doctor and researcher at St Mary's Hospital, Paddington, London, Fleming discovered the antibiotic penicillin in 1928. He successfully isolated the chemical from the mould Penicillium notatum, but could not purify the compound. During WW2 Sir Howard Walter Florey and Ernst Boris Chain developed a means of producing penicillin on an industrial scale. Together with Fleming they shared the Nobel Prize in 1945. Their work on producing a 'wonder drug' saved millions of lives. (Photo by Daily Herald Archive/SSPL/Getty Images)