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Alexander Fleming Laboratory, London

Fleming Laboratory at St Mary's Hospital, third floor, corner window.


The career of Alexander Fleming illustrates the wisdom that life shouldn't be too tidy. Certainly the early part of his career wasn't very organised. He moved to London from Scotland in 1895 and worked as a shipping clerk, a job which he hated. It was only a fortunate inheritance that opened up the possibility of medical training. Fleming chose St Mary's as his teaching hospital, not because it offered a great research tradition, but because it had a good water polo team. He arrived at St Mary's Hospital in 1901 and enrolled in the medical school there. Young Alexander was highly regarded, and in 1908 it seemed he might become a surgeon. But, surprising as it may seem there was no immediate vacancy for the man who had won the University of London Gold Medal for the best medical student of 1908. The sporty Alexander Fleming, happened to be a member of St Mary's Hospital Rifle Club. The rifle club president wished to retain Alexander, and suggested that he join the research department at St Mary's. This might not seem a good way to decide on a career, but this is how Alexander Fleming came to the research work that would revolutionise medicine.

Initially, however, there was no time for quiet research. World War One had broken out, and Fleming served in the Army Medical Corps. But even in the chaos of war, steps were being made towards Fleming's later discoveries. His experiences of watching soldiers die from infected wounds motivated his efforts in finding antibacterial agents. He realised that antiseptics placed on wounds by battlefield medics killed the body's defensive cells as powerfully as they killed invading bacteria. He had to watch doctors using antiseptics when it was clear they were useless, or actually making things worse. Even today antiseptic creams which have no value are regularly sold in chemist shops.

Following the war Fleming went back to his laboratory at St Mary's and patiently tried to find antibacterial agents. Once again it was untidiness that eventually helped him along. On 3rd September 1928, after returning from a holiday, he noticed a petri dish containing staphylococci which had been put in a sink ready for washing before going away. Mould was growing in the petri dish, and around the mould all the staphylococci were dead. Fleming realised that something in the mould must be having an antibacterial effect. It has been suggested that it was Fleming's natural messiness which allowed this discovery to happen. If he had washed up before going on holiday the mould would never have grown. Standing in what appeared to be his orderly laboratory I asked the ladies who work at the Fleming Museum, and who had known him, whether they thought he was messy. They gave the impression that in many ways Fleming was a fastidious man. He wouldn't allow the window to be opened, wanting to prevent all kinds of unknown foreign bodies from Praed Street getting in and landing on his petri dishes. So the idea that the crucial mould spore blew in through an open window seems to be a myth. But Fleming was "a boffin" to use my guide's words. He was vague, and was quite likely to be the sort of person not to conscientiously do his washing up. Also there was a laboratory just below Fleming's where work was being done on moulds, so the mould spore probably derived from there.

Fleming extracted the active agent from the mould, called penicillium notatum, and called it penicillin. There were practical difficulties in producing penicillin in large quantities. Shortly before World War Two a research team in Oxford, led by Howard Florey, began work on penicillin. By February 1941 they had enough penicillin to start treating an Oxford policeman who contracted a potentially fatal infection from a scratch while gardening. It is difficult to believe now that a scratch could end a life, but that's how things were before this drug was available. The policeman, Albert Alexander, responded well, but sadly supplies of penicillin ran out before his recovery was complete. Although the team tried extracting penicillin from Albert Alexander's urine, he died.

Florey and his colleague Norman Heatley then moved to the Northern Regional Research Laboratories at Peoria, Illinois, escaping the wartime conditions that made work so difficult in Britain. There they discovered a faster growing strain of mould on a rotting melon in a Peoria market. This, combined with deep tank fermentation techniques, meant that large scale production of penicillin was finally possible. This was a turning point in medicine. The lives of millions of people were saved by penicillin, and by the antibiotics that came after it.

The laboratory used by Alexander Fleming has been recreated at St Mary's Hospital in Praed Street, Paddington, London.

There is an education programme, involving videos and a display. Staff will visit schools and give talks on Fleming's work.


Opening Times: Please use contact details below.

Address: Alexander Fleming Laboratory, St Mary's Hospital, Praed Street, London W2 1NY

Directions: The nearest Underground station is Paddington. As you come out of the station cross over Praed Street in front of you and turn right. St Mary's Hospital is a couple of hundred yards along Praed Street. Go through the main entrance and follow signs. If a guide isn't present in the reception room ring the bell on the wall. Click here for an interactive road and satellite map centred on the Alexander Fleming Laboratory.

Access: Wheelchair access is not possible.


telephone: 020 3312 6528


web site:







©2007 InfoBritain (updated 11/13)