Alexander Fleming was a Scottish physician-scientist who discovered penicillin in 1928 while working at St. Marys Hospital in London. He noticed that a mould growing on a Petri dish of Staphylococcus bacteria was preventing the bacteria around it from growing. He identified that the mould produced a self-defence chemical that could kill bacteria and named the substance penicillin. Although Fleming published his findings in 1929, the scientific community initially showed little interest in his work. It was left to his fellow Nobelists, Howard Florey and Ernst Chain, to demonstrate in 1940 that penicillin could be used as a therapeutic agent to fight a large number of bacterial diseases. The simple discovery and use of the antibiotic agent has saved millions of lives, and earned Fleming, together with Florey and Chain, the 1945 Nobel Prize in Physiology/Medicine.