People of Science: Alexander Fleming and Howard Florey

People of Science with Brian Cox - Dame Sally Davies (2018-02-12) by The Royal SocietyThe Royal Society

Portrait of Alexander Fleming by Herbert de Gray (1910-1985)The Royal Society

Alexander Fleming & the discovery of penicillin

Alexander Fleming (1881-1955), FRS FRSE FRCE, was educated as a medical doctor before becoming a bacteriologist. As a captain in the Royal Army Medical Corps during WW1, he observed the devastation caused by septis, as the antiseptics used to treat soldiers wounds, in fact, sheltered bacteria. His research studied antibacterial substances to improve treatment of infections. 

Royal Society Fellowship election certificate for Alexander Fleming Royal Society Fellowship election certificate for Alexander Fleming (1943) by The Royal SocietyThe Royal Society

Fleming was elected Fellow of the Royal Society in 1943, for his discovery of lysozyme (an enzyme with antibacterial properties), of penicillin and most generally for 'many useful contributions both to systematic bacteriology and to laboratory technique'.

By Hans WildLIFE Photo Collection


The discovery of penicillin has now become a mythical moment in the history of medicine: on Friday 28 September 1928, rather than discarding a petri dish containing a culture of staphylococcus which had been contaminated by a mould, Fleming observed it under the microscope.

By Fritz GoroLIFE Photo Collection

Fleming observed that the mould had destroyed the staphylococci in its immediate proximity.

Intrigued by this disinfecting property, Fleming isolated the mould, identified it as belonging to the penicillium family and grew a pure culture of it, coining the term 'penicillin'.

Howard Florey and his team at the William Dunn School of Pathology, University of Oxford by AnonymousThe Royal Society

Howard Florey & the Oxford School of Pathology: Mass production of antibiotics

Nearly a decade after the discovery of penicillin, an Australian physiologist, Sir Howard Florey (bottom middle; 1898-1968), and a German biochemist, Ernst Boris Chain (2nd row right;1906-1979), formed a team at the Oxford School of Pathology to take Fleming's discovery further. 

Trail Blazers - cartoon showing key medical discoveries, Ben Harrison, 07/11/1944, From the collection of: The Royal Society
Show lessRead more

In 1940, after conclusive tests on animals, Florey and his team demonstrated the antibacterial effects of penicillin on people.

Suggestions for a pilot-scale penicillin extraction plant (1941) by Norman Heatley (1911-2004)The Royal Society

Florey's team devised a method to produce a stable and more powerful version of the drug. Despite transforming their lab into a small manufacture, the team suffered from a lack of equipment and funds, so could therefore only produce small amounts of the drug. Enough to demonstrate its effects conclusively, but not enough to be able to supply beyond clinical trials. 

Photograph of Howard Florey in laboratory, 1925. (1925) by AnonymousThe Royal Society

Florey lobbied successfully American pharmaceutical companies to produce penicillin G. Yet, in 1941-42 the productions by Merck & Co or Pfizer remained very limited. Florey had not patented the drug, which he thought should be of benefit to all. 

Penicillin (1944-06) by Fritz GoroLIFE Photo Collection

As the USA entered into WWII, the American War Production Board was eager to supply the Allied Forces with the wonder drug. The Board devised a plan which led to mass production in 1944 and its patenting in 1945. 

Alexander Fleming, Nobel Prize Lecture Alexander Fleming, Nobel Prize Lecture (1945) by Alexander Fleming (1881-1955)The Royal Society

Nobel Recognition

Alexander Fleming, Howard Florey and Ernst Boris Chain were awarded jointly the Nobel Prize in Physiology or Medicine in 1945, "for the discovery of penicillin and its curative effect in various infectious diseases". The Royal Society archives hold different drafts of the speech that Fleming and Florey gave to the Swedish Academy. 

Howard Florey's visit to the USSR Academy of Sciences (1965) by UnknownThe Royal Society

Sir Howard Florey, PRS

Howard Florey was elected 50th President of the Royal Society in 1958. His presidency was one of change for the Society: he relocated it physically from Burlington House to our current address on Carlton House Terrace. He also instituted a new Royal Medal and took part in an Anglo-American Mission which led him to the USSR to discuss advances in the field of medicine.  

Synthetic Penicillin. (1947-01) by Andreas FeiningerLIFE Photo Collection

Dorothy Hodgkins: towards molecular structure

Dorothy Crowfoot Hodgkin FRS (1910-1994) confirmed the 3D chemical structure of penicillin using X-ray crystallography. She was awarded the Nobel Prize in Chemistry for devising this method in 1964. The molecular formula of penicilin is C16H18N2O4S. With the key contributions of Fleming, Florey and Hodgkin, the discovery and study of penicillin, is one closely related to the Royal Society. 

Credits: Story

© Royal Society 2017

For more information about the Royal Society Library and Archive please visit our website:

Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
Explore more
Related theme
Once Upon a Try
A journey of invention and discovery with CERN, NASA, and more than 100 museums around the world
View theme
Google apps