Florey and the Miracle Mould

“The Adelaide Scientist Whose Vision, Leadership and Research Made Penicillin Available to Mankind”

Howard Florey Display

In 1945, Sir Alexander Fleming (1881-1955), Sir Ernst Chain (1906-1979) and Sir Howard Florey (1898-1968) received the Nobel Prize in Physiology or Medicine for their discovery of penicillin. The groundbreaking discovery of its curative properties transformed the treatment of infectious diseases and is credited with saving over 500 million lives worldwide. [1]

Born in Adelaide, South Australia, Florey graduated from the University of Adelaide with a Bachelor of Medicine and Bachelor of Surgery (M.B. B.S.) in 1921. He went on to study and work in major institutions across England, as well as in Europe and America, before being appointed in 1935 as Head of the Sir William Dunn School of Pathology at Oxford University. It was here that he, Chain, and Norman Heatley (1911- 2004) confirmed Fleming’s decade earlier observations and successfully extracted and purified penicillin.

To commemorate the 50th anniversary of Florey’s Nobel Prize achievement, Dr Richard Brock – influenced by the University of Oxford Alumni Network of South Australia –curated an exhibition highlighting Florey’s life and scientific achievements. Initially hosted at the Barr Smith Library, the collection featuring rare memorabilia and artefacts would soon travel around Australia. 

In collaboration with the History Trust of South Australia’s State History Centre, Dr Brock develop an interactive, educational exhibition that showcased Florey’s life, career and research, including a vessel containing a living culture of Fleming’s original strain of Penicillium notatum (now Penicillium chrysogenum), cultivated by University of Adelaide Professor David Ellis. 

The exhibition featured an array of captivating displays that brough Florey’s world to life. Visitors could immerse themselves in an interactive audio-visual program and a VCR slide-projection montage whilst exploring the memorabilia taken from Florey’s workspace and peers at Oxford University. Highlights of the exhibition included a microscopic demonstration of penicillium notatum, a micromanipulator developed specifically for Florey, and a microscope like his own. Authentic medical instruments used by Florey were complemented by graphic panels illustrating the chemical structure of penicillin and traced its journey from discovery to large-scale production in the UK, US, and Australia. The exhibition also showcased penicillin’s pivotal role in WWII and its enduring impact on modern medicine. 

The exhibition debuted at the South Australian Museum (SAM) in 1995 and achieved remarkable success. In 1996, the exhibition toured to “Scienceworks” in Melbourne, Victoria and received over 47,000 visitors.

Encouraged by the success of the Adelaide and Melbourne displays, the Florey Medical Chapter of the University of Adelaide, funded by the ‘Visions of Australia’ grant, toured across major institutions and regional centres around Australia between 1998 and 2000. Venues included the Western Australia Museum, Tasmanian Museum and Art Gallery, and the Newcastle Regional Museum, amongst others.

Florey and the Miracle Mould aimed to inspire future generations. Dr Brock hoped to make Florey a household name, influencing young minds to pursue careers in science. The exhibition is a testament to how one visionary scientist helped change the course of medicine.

Powerhouse Museum Florey and the Miracle Mould Exhibition Photographs

Photographer: Marinco Kojdanovski

Reproduced courtesy of: Powerhouse Museum

Exhibition Design and Visitor Engagement

Florey and the Miracle Mould was created as a tribute to Florey’s life and achievements, as well as to spark curiosity and inspire younger generations to explore careers in STEM. The exhibition offered families and school groups an enjoyable holiday activity, stimulating curiosity and perhaps even kindling an interest in the power of medicine.

Dr Brock envisioned the exhibition as a long-term initiative, hoping it would cement Florey’s name in Australian history alongside figures such as Sir Douglas Mawson and Dawn Fraser. 

To promote the exhibition, newsletters and posters were widely distributed. 

In preparation, the University of Adelaide reached out for materials relating to Florey’s scientific contributions. To their delight, many institutions and individuals responded generously, donating and loaning items for display. Among the most notable acquisitions were original laboratory equipment from the Sir William Dunn School of Pathology. 

Key contributors included Dr Heatley, Lady Margaret Florey (Florey’s second wife), and Mrs. Doris Kent (Widow of Florey’s Laboratory Assistant, James Kent). Their contributions included photographs, dissecting instruments and culture vessels. Larger institutions such as the Sir William Dunn School of Pathology and the Women’s and Children’s Hospital loaned specialised equipment, including a micromanipulator – a device used for precise interaction with samples under a microscope – and a binocular microscope for demonstrating Penicillin notatum. 

The exhibition also included an educational program designed and produced by Mark Blencowe for visiting school groups, as well as a biology project created by David Ellis, Affiliate Associate Professor in the School of Biological Sciences at the University of Adelaide, for biology classrooms which proved quite popular!

The biology classroom kits contained a culture of penicillium notatum, a water suspension of a non-pathogenic bacterium Sarcina lutea and some Mueller-Hinton agar (MHA) plates. Students were instructed to swab the Sarcina lutea suspension onto the agar plate. Once the plate was swabbed, they were instructed to cut out a small agar block from the penicillium notatum culture and place it in the centre of the plate. The experiment demonstrated the original “Oxford” strain of penicillium notatum that was used by Florey in the 1940s, and the antibiotic activity of penicillin, recreating Flemmings original observations.

The popularity of the exhibition exceeded expectations. Over two years touring Australia, and several years placed at the Melbourne Museum, Florey and the Miracle Mould attracted over 1.9 million attendees. 

Howard Florey Medical Instruments

Sir Howard Walter Florey 
(24 September 1898 – 21 February 1968)

Howard Florey was born in Adelaide, South Australia, the youngest child and only son of Joseph and his second wife Bertha Mary Florey. Joseph had migrated to Australia from England in 1882 and established a successful boot manufacturing business. [2]

During his youth, Florey was vulnerable to “chesty” conditions, contracting pneumonia in 1912 and 1914, alongside recurrent bronchitis. [3] Despite his susceptibility to poor health, he remained an outstanding student. His sisters’ careers in medicine – Hilda Gardner (née Florey) as a pathologist and Anne Florey as a nurse – no doubt influenced his own ambitions for a career in medicine. His disinterest in the family trade was also a contributing factor. 

Florey enrolled at the University of Adelaide Medical School in 1916 and was editor of the Medical Students' Society's Review and the Adelaide University Magazine. It was during his time as editor that he met Ethel Reed (1900 – 1966), who would go on to become both his wife and a key figure in the clinical testing of penicillin. After graduating in 1921, Florey spent the following years travelling through England and the US, pursuing research opportunities, receiving scholarships, appointments and positions in top universities, and developing his research wherever his passion lay.

His most significant work came at Sir Dunn School of Pathology department within the University of Oxford where he, Chain and Heatley, successfully isolated penicillin, leading to its manufacture and medical use. 

Alexander Fleming: How His Chance Discovery Changed the World of Medicine

While exact circumstances are debated, it is believed that in 1928 Alexander Fleming, after coming back from holiday to his lab at St Mary's Hospital, London, observed a strange reaction in one of his petri dishes. [4] Whilst studying staphylococci bacteria, a fungal contamination appeared on one of the petri dishes and caused the surrounding staphylococci cells to lyse. This fungal contamination would later be identified as Penicillium notatum. 

Penicillin is a powerful antibiotic; with its antibacterial properties, it works by damaging the bacterial cell wall allowing the body’s immune system to fight and clear away the infection more effectively. It is not the mould itself that prevents the growth of bacteria, but the substance it excretes. 

Despite publishing his findings in 1929 and attempting to replicate the growth of penicillin in the years that followed, Fleming and others were unsuccessful in their attempts to isolate the compound and research interest into the compound waned.

Florey, Chain, Heatley and Kent: Unlocking Penicillin’s Potential

In 1938, Florey and Chain rediscovered Fleming’s 1929 publication whilst searching for new research opportunities in naturally occurring antibacterial substances. Ironically, Florey was an editor of the British Journal of Experimental Pathology where Fleming’s original paper was published, a paper Florey most likely had seen before.

Driven by their shared interest in microbial antibacterial properties, Florey and Chain assembled a team at the Sir William Dunn School of Pathology at Oxford. Alongside Heatley and James Kent, Florey’s trusted technician assistant, they worked together to figure out how to extract, purify and produce penicillin in large quantities. 

Florey and Kent worked tirelessly, conducting animal trials to test penicillin's effectiveness. An example of one of the teams’ experiments occurred on the 25 May 1939: eight mice were injected with a strain of Streptococcus. If left untreated, in humans this dose would lead to further inflammation of organs and rheumatic fever, and in severe cases, it is life-threatening. In mice, it is almost always fatal. Of the eight mice injected with a lethal dose of Streptococcus, half were also injected with penicillin. The controlled mice, those not injected with penicillin, soon died. The treated mice survived. [5] These experiments confirmed the remarkable potential this substance had in combating bacterial infections. However, concerns arose due to the lack of compound required for treatment, which could not yet be produced for clinical use.

Heatley, the ‘unsung hero’ in the story of penicillin, designed a way to produce larger quantities of penicillin. To do so, he suggested a different process of purification that stabilised penicillin so that it could be concentrated effectively. Recognising the need for greater output, he also repurposed everyday items, such as porcelain bedpans, as vessels for cultivating penicillin mould. [6] His new and innovative designs helped make Oxford laboratory the first penicillin factory.

Florey and his teams’ collaborative efforts marked a turning point in history, paving way for penicillin's mass manufacture and its lifesaving role during WWII.

The First Human Trial: An Unexpected Opportunity Arises

With the animal trials completed, it was time to explore penicillin’s potential in human treatment. 

In 1941, 43-year-old Constable Albert Alexander, developed a severe abscess across his face and body after a bombing raid in Southampton during WWII or by a scratch from a rose thorn – the scenario is contested. [7] His condition deteriorated rapidly; however, upon an initial injection of penicillin, he showed signs of improvement. Unfortunately, due to limited supplies, his infection returned, leading to his passing. [8]

To stretch resources, researchers discovered that the body excreted up to 80% of penicillin in urine which could be recovered. Dr. Ethel Florey, supervising the clinical trials, led the ‘P-Patrol’, collecting patients’ urine for recycling at the penicillin production unit at the Sir William Dunn School of Pathology. 

This breakthrough convinced Florey of penicillin's potential. Jumping over to the US, after realising England alone could not produce the amounts needed during the war, Florey successfully persuaded the United States pharmaceutical companies to scale up production. The supplies accompanying the troops during the D-Day landings significantly reduced the death toll that usually would have been the result of untreated infected wounds. [9]

Penicillin Production

Important Figures and Influences

Sir Ernst Boris Chain
(19 June 1906 - 12 August 1979)

Ernst Chain was born to a German mother and a Russian father, both of whom believed that the “only worthwhile occupation in life was the pursuit of intellectual activities”. [10] Encouraged by this philosophy, his parents provided tutors in mathematics and philosophy, fostering his pursuit of knowledge.

Chain graduated from Friedrich Wilhelm University (now Humboldt University) in 1930 with degrees in chemistry and physiology. Amidst growing unrest in Germany, he left for England in 1933. He later made a point to note that his departure from the country was not due to fear of Nazi prosecution but out of moral disgust. [11]

With £10 in his pocket when he arrived in England, Chain secured a job at the University College Hospital, London, before becoming a lecturer of pathology at Oxford University in 1935.  His earlier research explored biochemical mechanisms, including why certain snake venoms attack the central nervous system.

Fascinated by enzymes, a type of protein which accelerates chemical reactions, Chain completed his study of snake venom at Cambridge University before joining Florey’s team at Oxford. Chain and Florey quickly built a rapport that enabled easy collaboration. They worked alongside one another, conducting systematic investigation of the properties of naturally occurring antibacterial substances.

Focusing on the study of lysozymes, a substance Florey had been interested in for many years, Chain confirmed Fleming’s earlier suspicions that the molecular substance was actually an enzyme but yielded no further results. Seeking new directions, Chain discovered Fleming’s 1929 journal article on penicillin which kickstarted his and Florey's work into the antibiotic.

Norman George Heatley
(10 January 1911 – 5 January 2004)

Norman Heatley’s pivotal role in developing penicillin went largely unnoticed until 1990, when the University of Oxford presented him with an honorary Doctorate of Medicine. He has since been titled the “unsung” hero of penicillin, as without Heatley’s ingenuity and passion, penicillin would not have entered the world at the time it did. [12]

Heatley attended St John’s College, Cambridge and graduated in 1933 with a degree in Natural Sciences and completed his PhD in 1936. He then moved to the University of Oxford where he became a fellow of Lincoln College and worked under Florey.

The challenges that had stalled penicillin's research and production were overcome by Healtey’s critical thinking and ingenuity. Tasked with extracting sufficient amounts of penicillin for Chain to study, Heatley invented the technique of ‘back-extraction’ and in 1940, was successful in extracting and purifying enough penicillin for the first animal tests. [13]

The difficulties imposed by the UK war time restrictions posed further challenges for the Oxford team to produce the required amount of penicillin for clinical trials. With limited resource and material shortages, Heatley designed stackable ceramic ‘bed pan’ vessel that facilitated large-scale mould cultivation. Soon after the successful animal tests, 600 vessels were sealed and stacked, marking the beginning stages of penicillin production at the Sir William Dunn School for clinical testing. [14]

Heatley later accompanied Florey on his trip to the United States, transporting the penicillin-producing mould by coating their coats with spores as to safeguard it from enemy hands. While Florey journeyed back to Oxford, Heatley remained collaborating with Dr. A. J. Moyer to scale up penicillin production to meet wartime demands. His innovative adjustments to the process significantly increased yields. However, during their time together, Heatley noticed Mr Moyer changed in disposition, withholding pieces of information. It was a surprise when their joint research was published without his name. Dr. Moyer, to simplify the patenting process, erased Heatley’s contributions.

A show of his good nature, Heatley admits to being more amused than angered by this, remaining quiet about his role.

Mary Ethel Hayter Reed
(1 October 1900 – 10 October 1966)

"It must never be forgotten that if it wasn’t for Ethel, penicillin would not have been introduced into medical practice when it was". [15]

Ethel Florey (née Reed) met Howard Florey whilst studying medicine at the University of Adelaide. She graduated in 1924 as the only woman in her year despite recurrent health issues and secured an internship at the Adelaide Children's Hospital. Content to remain in Adelaide, she eventually joined Florey in England, and they married in 1926.

Her worsening health and hearing impairment was a constant source of anxiety and frustration to both she and Florey and curtailed their hopes of joint research, though they did co-author two papers in 1929. [16]

During WWII Ethel led the Oxford Regional Blood Transfusion Service and later assisted in the penicillin trials at the Radcliffe Infirmary, Birmingham Accident Hospital, and other military hospitals. Whilst at Radcliffe Infirmary, Ethel alerted Florey to Constable Albert Alexander, one of the first patients treated with penicillin. The treatment was unsuccessful, but only due to the insufficient amounts of penicillin that could be produced at the time. With increased production, a greater number of patients could be treated.

The William Dunn School of Pathology treated fifteen seriously ill patients and over 170 localised infections. [17] Ethel became known as a ‘corpse retriever’, with doctors sending patients to her department who had been unsuccessfully treated with other medication. Despite the name sounding distasteful, this helped penicillin appear more impressive, bringing patients back from the dead.

Following the war, Ethel continued treating patients with penicillin and earned her Doctor of Medicine (in absentia) in 1950. Despite her persistent ill-health that worsened as the years progressed, her devotion to Oxford and her colleagues never wavered, stating she could “never desert those wonderful people [at Oxford]. I worked with them all through the war and to leave them forever would be deserting.” [18]

Ethel passed away in 1966.

James 'Jim' Kent
(c.1913 - unknown)

Completing his elementary education in 1927, Kent faced the challenge of finding work in a period of widespread unemployment. Through his sister’s position at an employment bureau, he secured a role as a laboratory in the Pathology Department at the University of Oxford, driven by his desire to become a vet.

One morning, whilst sweeping Florey’s lab, Kent bumped into the researcher known for his demanding standards. Regardless of the reputation that proceeded him, when Florey offered Kent a position as his personal technical assistant, Kent grasped it with both hands.

According to Macfarlane, “Kent was invaluable, not only as the most skilled and efficient animal assistant but as Florey’s tireless and devoted laboratory companion”. [19]

Kent and Florey developed a professional partnership that spanned 40 years, with Kent accompanying Florey to every appointment both in the UK and US.

In 1940, Kent helped Florey on the pivotal experiments involving cats, rats, rabbits, and mice to determine penicillin's absorption, excretion, and potential toxicity.

The University of Oxford recognised Kent in 1978 for his contributions by awarding him an honorary Master of Arts degree.

References:

[1] Sir William Dunn School of Pathology (n.d.) Our history. University of Oxford. https://www.path.ox.ac.uk/centenary/our-history/ (accessed 25/11/2025)

[2] Macfarlane, R. G. (1979). Howard Florey, the making of a great scientist. Oxford University Press.

[3] Williams, T, I. (1984). Howard Florey; penicillin and after. Oxford University Press.

[4] Lax, E. (2004). The mould in Florey’s coat; the remarkable true story of the penicillin miracle. Little, Brown.

[5] Gaynes, R. (2017). The discovery of penicillin—new insights after more than 75 years of clinical use. Emerging Infectious Diseases vol. 23, 5. https://pmc.ncbi.nlm.nih.gov/articles/PMC5403050/#:~:text=Florey%20oversaw%20the%20animal%20experiments,treated%20mice%20were%20still%20alive.

[6] Oxford University (2024). The lasting legacy of Norman Heatley, the unassuming penicillin pioneer who changed the course of medicine. https://www.medsci.ox.ac.uk/news/the-lasting-legacy-of-norman-heatley-the-unassuming-penicillin-pioneer-who-changed-the-course-of-medicine

[7] Lax, E. (2004). The mould in Florey’s coat; the remarkable true story of the penicillin miracle. Little, Brown.

[8] Bickel, L. (1972). Rise up to life: a biography of Howard Walter Florey who made penicillin and gave it to the world. Angus and Robertson

[9] Wood, J. (16 July 2010). Penicillin: the Oxford story. University of Oxford. https://www.ox.ac.uk/news/science-blog/penicillin-oxford-story#:~:text=Florey%20and%20Chain%20began%20work,purify%20penicillin%2C'%20says%20Sidebottom.

[10] Lax, E. (2004). The mould in Florey’s coat; the remarkable true story of the penicillin miracle. Little, Brown.

[11] Lax, E. (2004). The mould in Florey’s coat; the remarkable true story of the penicillin miracle. Little, Brown.

[12] Oxford University (2024). The lasting legacy of Norman Heatley, the unassuming penicillin pioneer who changed the course of medicine. https://www.medsci.ox.ac.uk/news/the-lasting-legacy-of-norman-heatley-the-unassuming-penicillin-pioneer-who-changed-the-course-of-medicine

[13] Brack, P. (2015). Norman Heatley: The forgotten man of penicillin. The Biochemist (London, England), 37(5), 36–37. https://doi.org/10.1042/bio03705036

[14] Macfarlane, R. G. (1979). Howard Florey, the making of a great scientist. Oxford University Press.

[15] Bickel, L. (1972). Rise up to life: a biography of Howard Walter Florey who made penicillin and gave it to the world. Angus and Robertson

[16] Macfarlane, R. G. (1979). Howard Florey, the making of a great scientist. Oxford University Press.

[17] Lax, E. (2004). The mould in Florey’s coat; the remarkable true story of the penicillin miracle. Little, Brown.

[18] Bickel, L. (1972). Rise up to life: a biography of Howard Walter Florey who made penicillin and gave it to the world. Angus and Robertson

[19] Macfarlane, R. G. (1979). Howard Florey, the making of a great scientist. Oxford University Press.

[20] Adelaide AZ. (2025). Howard Florey’s fame obscures distinguished medical careers of his sister Hilda and wife Mary after Adelaide Uni. Adelaide AZ. https://adelaideaz.com/articles/howard-florey-s-fame-obscures-distinguished-medical-careers-of-his-sister-hilda-and-wife-mary-after-adelaide-university (accessed 17 December 2025)

[21] Adelaide AZ. (2025). Howard Florey’s fame obscures distinguished medical careers of his sister Hilda and wife Mary after Adelaide Uni. Adelaide AZ. https://adelaideaz.com/articles/howard-florey-s-fame-obscures-distinguished-medical-careers-of-his-sister-hilda-and-wife-mary-after-adelaide-university (accessed 17 December 2025)

[22] Adelaide AZ. (2025). Howard Florey’s fame obscures distinguished medical careers of his sister Hilda and wife Mary after Adelaide Uni. Adelaide AZ. https://adelaideaz.com/articles/howard-florey-s-fame-obscures-distinguished-medical-careers-of-his-sister-hilda-and-wife-mary-after-adelaide-university (accessed 17 December 2025)

[23] VWMA (2025) John Forrest Gardner. https://vwma.org.au/explore/people/62463

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