PENICILLIN – Development 1938–1941

Sir William Dunn School of Pathology, South Parks Road, Oxford

Alexander Fleming famously identified the antibiotic properties of penicillin in 1928 when he observed that a curious fungus had destroyed bacteria on a plate left in his laboratory while he was on holiday. It is less well known that pioneering work on the isolation and purification of penicillin to make it a viable treatment of bacterial disease was performed by a team of scientists at the Dunn School 1938–1941. While there had been some treatments with antibacterial substances before, especially the sulpha drugs in the 1930s, the groundbreaking work on penicillin revolutionised modern medicine and began the golden era of antibiotics which we have long taken for granted. 

Dunn School

Howard Florey became Head of Pathology at the Dunn School (above) in 1935 and recruited an interdisciplinary team of scientists to investigate the properties of antibacterial substances.  The members of that team were the biochemists Ernst Chain, Edward Abraham and Norman Heatley, the bacteriologist Arthur Gardner, Jena Orr-Ewing, Margaret Jennings, and Ethel Florey. Chain came upon Fleming’s paper on Penicillium notatum in the British Journal of Experimental Pathology and it was decided to do further research on its potential as a miracle drug. Chain succeeded in growing the elusive and unstable mould and extracting the antibacterial constituent. Norman Heatley (who has his own blue plaque on his former Marston home) ingeniously devised a counter-current apparatus for the multi-automated process of production, utilising all kinds of vessels such as bedpans and milk churns in a time of wartime shortages. The important individual contributions of these key figures were memorably stated by Professor Sir Henry Harris who succeeded Florey as Head of the Dunn School: “Without Fleming, no Chain; without Chain, no Florey; without Florey, no Heatley; without Heatley, no penicillin.”

At the former Radcliffe Infirmary on 12 February 1941 Albert Alexander, gravely ill from a septic wound, was the first patient to be treated with the new drug.  He rallied very quickly but later relapsed and died as there was insufficient amount of the drug available to continue the course. Five other patients were treated, four making a complete recovery, confirming penicillin as a miracle drug. The next priority was to achieve mass production and to do so urgently. Florey and Heatley flew to America to negotiate with big pharmaceutical companies there. By 1944 penicillin was being mass produced with the help of laboratories in the USA, to the immediate benefit of wounded soldiers who before the advent of penicillin would have died from septicaemia.

In 1945 Howard Florey and Ernst Chain were awarded the Nobel Prize for Physiology or Medicine for the development of penicillin. The prize was shared with Alexander Fleming for his initial discovery. Florey, Chain and Fleming were knighted. Florey became Baron Florey of Adelaide and Marston (1965) and Provost of The Queen’s College, Oxford (1962–1968). He was admitted to the Order of Merit.


  • Sir William Dunn School of Pathology: The Discovery of Penicillin
  • Eric Lax, The Mould in Dr Florey’s Coat (2004)
  • Dr Eric Sidebottom, Oxford Medicine: A Walk Through Nine Centuries (2010)

The ceremony was held on 29 May 2018. Professor Matthew Freeman FRS, Head of Pathology at the Dunn School gave the main speech. Among those attending were the Lord Mayor of Oxford (Cllr Colin Cook), descendants of Florey’s team, and many medical scientists.

Photographs taken at the ceremony:

There was a related Blue Plaque ceremony on the same day at the old Radcliffe Infirmary.


Oxfordshire Blue Plaques Board

In this building
Howard Florey, Ernst Chain,
Norman Heatley & colleagues
first isolated and purified
for the treatment of
bacterial infection

Sir William Dunn School of
Pathology University of Oxford

© Oxfordshire Blue Plaques Board


Email: oxfordshireblueplaques@gmail.com