Alexander Fleming

Alexander Fleming was a Scottish physician and microbiologist who spent years studying bacteria when, in 1922, he discovered the enzyme lysozyme in his own nasal discharge, along with a bacterium he named Micrococcus lysodeikticus. Six years later, in 1928, he noticed that mould from the genus Penicillium rubens had contaminated a culture plate and killed the surrounding bacteria - what he'd stumbled onto was benzylpenicillin, later called penicillin G, a substance that would be described as "the single greatest victory ever achieved over disease". He shared the 1945 Nobel Prize in Physiology or Medicine with Howard Florey and Ernst Chain for the discovery and its curative effects. Knighted in 1944, Fleming later appeared on Time's list of the 100 Most Important People of the 20th century, the BBC's 100 Greatest Britons, and was voted third greatest Scot behind Robert Burns and William Wallace.