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 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 mold Penicillium notatum, but could not purify the compound.