Sir Alexander Fleming: The Farm Boy, the Mouldy Dish and the Real Story of Penicillin
Updated: 4 days ago
In late summer 1928, Alexander Fleming got back from a family holiday to find his bench at St Mary's Hospital in Paddington in its usual state. Culture plates of Staphylococcus bacteria were stacked up waiting to be cleaned. On one of them a blob of mould had taken hold, and the bacteria around it had died back into a clear ring.
That's the version everybody learns at school, and it's broadly true. But it skips a lot. It skips the experiment Fleming ran on his own snot, the pictures he painted with living germs, the rifle club that kept him in research, the odd two-month gap in his notebooks and the very public scrap over who actually deserved the credit. Here's the fuller story of the Ayrshire farm boy who ended up buried in St Paul's Cathedral.
Quick Answers
• Who was Alexander Fleming? A Scottish bacteriologist (1881 to 1955) who spent his entire career at St Mary's Hospital Medical School in London.
• When did he discover penicillin? He spotted the effect in 1928 and published it in the British Journal of Experimental Pathology in 1929.
• Did he turn it into a medicine? No. An Oxford team led by Howard Florey and Ernst Chain purified it and proved it worked in patients from 1940 onwards.
• Did he win a Nobel Prize? Yes. He shared the 1945 Nobel Prize in Physiology or Medicine with Florey and Chain, a year after being knighted.
• When did he die? On 11 March 1955 in London, aged 73. His ashes are in the crypt of St Paul's Cathedral.
A Farm Boy From Ayrshire
Fleming was born on 6 August 1881 at Lochfield, a hill farm near Darvel in Ayrshire. He was one of eight surviving children in a farming family, and his father Hugh died when Alexander was seven. His schooling started in a tiny moorland school, moved on to Darvel and then to Kilmarnock Academy, and at 13 he headed to London to live with his older half-brother Tom, who was a doctor (Science History Institute).
Medicine wasn't the plan at first. He studied at the Regent Street Polytechnic and then spent a few years as a clerk in a shipping office, which he found mind-numbing. A small legacy from an uncle in 1901 gave him a way out, and he won a scholarship to St Mary's Hospital Medical School. He never really left the place again.
The Rifle Club That Kept Him in Research
Fleming's choice of medical school wasn't exactly scientific. He picked St Mary's partly because he'd once played water polo against their team. In 1900 he'd also joined the London Scottish Regiment, a volunteer unit, along with two of his brothers. They were signed up during the Boer War but never saw action, and spent their time getting very good at shooting and swimming (Biographics).
That marksmanship turned out to matter. After qualifying in 1906, Fleming was leaning towards surgery, which would've meant leaving St Mary's. The captain of the hospital rifle club didn't want to lose a good shot, so he steered Fleming into a job in the Inoculation Department run by Sir Almroth Wright, the pioneering vaccine researcher. It's one of the stranger sliding doors moments in medical history: the man who found penicillin ended up in a lab partly so St Mary's could keep winning shooting competitions.
Before the war, Fleming also took on patients for Salvarsan, Paul Ehrlich's new arsenic-based treatment for syphilis, which had to be injected carefully into a vein. Syphilis was a genuinely terrifying disease before antibiotics, as the grim last years of Al Capone make clear.
Boulogne and the Problem With Antiseptics
During the First World War, Fleming served in the Royal Army Medical Corps and worked in a wound research lab in Boulogne run by Wright. The Western Front produced injuries on an industrial scale, and just getting the wounded off the battlefield was hard enough, as the story of the mercy dogs who searched no man's land shows. Once men reached hospital, infection killed huge numbers of them anyway.
Fleming's work there was important and a bit uncomfortable for the medical establishment. He showed that chemical antiseptics like carbolic acid couldn't reach bacteria in deep, jagged wounds, and that they did real damage to the white blood cells the body relied on to fight infection (Science History Institute). In other words, the standard treatment was often making things worse. It left him hunting for something that would kill germs without harming the patient.
The Snot Experiment
His first big find came from a head cold. In late 1921, Fleming cultured a sample of his own nasal mucus. His research student V.D. Allison noticed that bacteria near the blob of mucus had been wiped out, looking "translucent, glassy and lifeless" (Scientific American).
The substance responsible was an enzyme Fleming named lysozyme, and he went on to find it in tears, saliva, blood serum and all sorts of plant and animal tissue. It was a genuine discovery about how the body defends itself. When he presented it to the Medical Research Club in December 1921, though, nobody asked a single question. Using yourself as test material has a long history in medicine, from Fleming's nose to the Romanian pathologist Nicolae Minovici, who hanged himself for science, though Fleming's version was a lot less painful.
Lysozyme mostly worked against harmless bacteria rather than the ones that made people ill, so it never became a treatment. But it taught Fleming to look for germ-killing substances in unlikely places, and that paid off seven years later.
What Were Alexander Fleming's Germ Paintings?
Fleming had a playful streak that doesn't always make it into the textbooks. He was a member of the Chelsea Arts Club, and alongside ordinary watercolours he made pictures using living bacteria. He'd pick microbes with natural pigments, like red Serratia marcescens, purple Chromobacterium violaceum and yellow Micrococcus luteus, and paint them onto agar plates with a wire loop (Hektoen International).
The tricky part was timing. Different species grow at different speeds, so he had to inoculate each colour at the right moment for the whole picture to appear at once. His subjects included houses, ballerinas, soldiers and mothers feeding children (Smithsonian). He reportedly made a bacterial Union Jack for Queen Mary when she visited St Mary's, and she apparently wasn't terribly impressed.
Did Fleming Really Discover Penicillin by Accident?
Here's where the famous story gets messier. Fleming worked in a small lab in a building on Praed Street. Directly below was a lab run by the mycologist C.J. La Touche, who was studying moulds linked to asthma and didn't have proper fume hoods. The most widely accepted theory is that spores drifted up the stairwell and landed on Fleming's plate (Asimov Press).
Timing mattered too. In 1970, Fleming's former colleague Ronald Hare pointed out that a cool spell hit London from 28 July to 6 August 1928, with temperatures below 20°C. That suits mould nicely but slows staphylococci down, which would've given the mould a head start while Fleming was away.
There's also a puzzle in the paperwork. Fleming is supposed to have seen the plate on 3 September 1928, but his first notebook entry about the mould doesn't turn up until 30 October, and it describes a deliberately planned experiment rather than a happy accident. Several scientists later tried to recreate the discovery the textbook way and failed, because penicillin only kills bacteria while they're actively growing. It only works reliably if the mould gets going first. Historian Robert Root-Bernstein has suggested Fleming may actually have been screening things for lysozyme-like effects at the time. None of this is settled, and it doesn't take away from what he spotted. It just means the neat "mouldy dish" story is probably a simplified version of what happened.
Whatever the exact sequence, Fleming grew the mould, identified it as a Penicillium and found that the "mould juice" it gave off killed a wide range of harmful bacteria without hurting white blood cells. He named the substance penicillin and published his results in 1929.
Why Didn't Fleming Develop Penicillin Himself?
The paper barely made a ripple. Penicillin was hard to isolate, fell apart quickly and was produced in tiny amounts. Fleming mainly thought of it as a surface antiseptic and a handy lab tool for separating out bacteria.
Oddly, he never ran the obvious test of infecting mice and then treating them with it, which would have shown what it could do inside the body (Science History Institute). He kept the mould going and handed out samples, but by the mid-1930s the trail had largely gone cold.
Oxford Takes Over
In 1937, Howard Florey and Ernst Chain at Oxford's Sir William Dunn School of Pathology came across Fleming's paper and decided to have a proper go at it. Their team worked in wartime conditions with almost no budget, brewing mould broth in bedpans, milk churns, food tins and bathtubs. Six young women, later nicknamed the penicillin girls, were hired to tend the cultures: Ruth Callow, Claire Inayat, Betty Cooke, Peggy Gardner, Megan Lancaster and Patricia McKegney (Science Museum).
On 12 February 1941, Albert Alexander, a 43-year-old police officer, became the first patient to be treated with their purified penicillin. His infection had started with either a scratch from a rose thorn or an injury in a bombing raid, depending on which account you read, and it had spread so badly he'd lost an eye. Supplies were so short that the team recovered penicillin from his urine to reuse. He improved dramatically, then relapsed when the drug ran out and died (National Geographic).
Proper mass production came from the United States. At a government lab in Peoria, Illinois, researchers found that corn steep liquor boosted yields massively, and a mould picked off a rotting cantaloupe from a local market turned out to produce around six times more penicillin than Fleming's original strain. In March 1942, Anne Miller in Connecticut became the first American whose life was saved by it, and her dose used up roughly half the penicillin in the entire country (Yale School of Medicine). By D-Day, 2.3 million doses had been made ready for the Normandy landings.
Harry Lambert and the Battle for Credit
In August 1942, Fleming had a patient called Harry Lambert who was dying from an infection of the nervous system. Fleming got hold of penicillin from Florey's team in Oxford and injected it into Lambert's spinal canal, and he improved the very next day (Yale School of Medicine).
Then the press got involved. The Times ran a piece on penicillin on 27 August 1942 that didn't name anyone. On 31 August, Almroth Wright wrote in to say the credit belonged to Fleming. Two days later, the Oxford chemist Sir Robert Robinson replied that Florey deserved it just as much. According to historians who've looked at the episode, reporters had been tipped off in advance and turned up at St Mary's the morning Wright's letter appeared. The man suspected of arranging it was Charles Wilson, the dean of St Mary's Medical School, who later became Lord Moran and Winston Churchill's personal doctor (Dynamis).
Fleming was happy to chat to journalists. Florey mostly refused. So the newspapers had a friendly Scottish scientist with a great origin story on one side and a reluctant Australian on the other, and the public version of penicillin became Fleming's story. By the time the war ended, the legend had a momentum of its own.
Did Alexander Fleming Save Churchill's Life?
You might have seen a story online claiming that Fleming's father saved a young Winston Churchill from drowning, that Churchill's grateful father paid for Alexander's education and that penicillin later saved Churchill's life in 1943. It's a lovely tale, and none of it holds up.
The International Churchill Society traces it to a December 1944 article in Coronet magazine. Fleming was seven years younger than Churchill, there's no record of Churchill nearly drowning in Scotland and when Churchill had pneumonia in 1943 he was treated with M&B, a sulphonamide drug made by May and Baker, not penicillin. His doctor's diaries mention M&B and nothing about penicillin (International Churchill Society). That doctor was Lord Moran, the same man who helped put Fleming on the front pages. Churchill had plenty of genuine brushes with death, like his escape from a Boer prison camp, so he didn't need an invented one.
Fame, the Nobel and a Warning Nobody Heeded
Fleming was knighted in 1944, and in 1945 he shared the Nobel Prize with Florey and Chain. In his Nobel lecture that December he warned that bacteria could learn to resist the drug if people misused it. "The time may come when penicillin can be bought by anyone in the shops," he said, and he worried that people would underdose themselves and breed resistant germs (Nobel Lecture via JAC-Antimicrobial Resistance). More than 80 years on, antibiotic resistance is one of the biggest problems in global health, so he was bang on.
The honours came from some unexpected directions. In May 1964, bullfighters in Madrid paid for a monument to Fleming outside the Las Ventas bullring, sculpted by Emilio Laiz Campos, with an inscription thanking him on behalf of the matadors. Before penicillin, a goring often meant death from infection. The statue has been spray-painted since, although the graffiti that went viral in 2020 actually dated from 2015 and was aimed at the bullfighters rather than Fleming (Truth or Fiction).
Family, Loss and a Second Marriage
In 1915, Fleming married Sarah McElroy, an Irish nurse. Their only son, Robert, was born in 1924 and followed his father into medicine, becoming a GP (Biographics). Sarah died in 1949.
In 1953 he married Dr Amalia Koutsouri-Vourekas, a Greek doctor who'd been working in his lab at St Mary's. They had less than two years together. On 11 March 1955, Fleming died suddenly of a coronary thrombosis at home in London, aged 73 (Britannica). His ashes were placed in the crypt of St Paul's Cathedral, alongside Nelson and Wellington.
So Was It Just Luck?
The discovery of penicillin gets told as a fluke, and luck definitely played its part. If the most popular theory is right, the spores had to drift up the right stairwell and the weather had to cool down at exactly the right moment. But plenty of scientists had thrown out contaminated plates before. What Fleming brought was the habit of looking twice at things that went wrong, a habit he'd already shown with his runny nose in 1921.
He didn't make penicillin into a medicine, and the people who did got less credit than they deserved for a long time. But he saw it first, he named it and he kept the mould alive for a decade until someone could finish the job. His old lab at St Mary's has been recreated as the Alexander Fleming Laboratory Museum, so you can still see the cramped room where it all started.
FAQ
Was Alexander Fleming related to Ian Fleming?
No. Ian Fleming, who created James Bond, and his brother Peter came from a wealthy banking family with no link to the Ayrshire Flemings. If you're after the other Flemings, have a look at Ian Fleming's Jamaica and the adventures of Peter Fleming.
Did Fleming make money from penicillin?
Not directly. Penicillin was never patented by Fleming or the Oxford team, and the big commercial money went to the drug companies that mass-produced it.
Where can you see Fleming's lab?
His lab has been restored as a small museum at St Mary's Hospital on Praed Street in Paddington. Opening times are limited, so it's worth checking before you go.
