Sir Alexander Fleming (1881–1955)

Ayrshire roots and an unglamorous start

Alexander Fleming was born on a farm near Darvel, Ayrshire, in 1881, the third of four children; his father died when he was only seven. There was no obvious early trajectory toward scientific greatness — Fleming worked for four years in a London shipping office after school before an inheritance from an uncle let him enrol at St Mary's Hospital Medical School in Paddington in 1901, aged twenty. He proved an excellent student, earning his medical degree with distinction in 1906 and a bacteriology degree with a gold medal in 1908, and was retained at St Mary's as a lecturer — the institution where he would spend essentially his entire career.

The war that shaped his thinking about infection

Fleming's experience treating wounded soldiers on the Western Front during the First World War is not a side note to his later work — it is arguably the direct intellectual origin of it. Serving in the Royal Army Medical Corps from 1914, he observed that the standard treatment of the era, flooding wounds with antiseptic chemicals, frequently failed and sometimes actively worsened outcomes: antiseptics could kill surface bacteria while failing to reach deep infection sites, and in the process destroyed the body's own protective white blood cells along with the pathogens. Fleming published this finding in The Lancet in 1917. This wartime observation — that the medical establishment's confident standard treatment for infected wounds was fundamentally flawed — gave Fleming both the specific scientific question (is there a better way to fight infection?) and the professional scepticism toward received wisdom that shaped the rest of his career.

Lysozyme: the discovery that came before the famous one

Long before penicillin, Fleming made a genuine and interesting discovery that deserves more attention than it usually gets, precisely because it shows his later breakthrough was not an isolated fluke. In late 1921, while working with bacterial culture plates, Fleming found that nasal mucus he added to a contaminated plate created a clear zone where bacteria could not grow. Testing tears, sputum, blood, and egg white, he found the same antibacterial effect present across multiple bodily fluids, and named the responsible enzyme "lysozyme," publishing the findings in 1922. The discovery was met with almost total indifference from his scientific peers — his paper to the Royal Society reportedly drew no questions and no discussion. Lysozyme ultimately proved too weak against most disease-causing bacteria to become a useful drug, but the episode is directly relevant to what followed: Fleming had already spent years actively investigating natural antibacterial substances in the body, using exactly the kind of contaminated-culture-plate observation that would later produce his famous discovery. The 1928 breakthrough was not his first time noticing that something was inhibiting bacterial growth on a plate — it was at least his second.

September 1928: what actually happened is less certain than the textbook story

The conventional account, repeated in countless popular retellings, holds that Fleming returned from a summer holiday on 3 September 1928 to find a culture plate of staphylococci accidentally contaminated by an airborne mould spore, and noticed that bacterial colonies near the mould had been destroyed while those farther away remained healthy — prompting his famous remark, "That's funny." This version is broadly accurate in its outline, and Fleming's own later recollections support it in substance. But historians examining the documentary record have identified genuine problems with the precise, dramatised version of the story: no contemporary record actually documents the moment of discovery on the date usually cited, there is a gap of roughly two months before the observation first appears in Fleming's laboratory notebook, and — more fundamentally — penicillin is only effective against actively growing bacterial cells, not mature colonies of the kind already visible on an untouched plate, which raises real scientific questions about the mechanics of the standard story as usually told. Numerous attempts by later scientists to replicate the classic "left the plate on the bench and came back to a clean kill zone" scenario have failed under normal laboratory conditions.

Two serious alternative accounts have been proposed by historians of science. One, advanced by Ronald Hare in 1970, suggests Fleming inoculated staphylococci and mould together and then forgot to incubate the plate, with an unusual cold snap allowing the mould to establish itself before the bacteria could grow — an improbable but not impossible sequence of coincidences. A second, from Robert Root-Bernstein in 1989, argues Fleming was not simply working on staphylococci at all but was continuing his lysozyme research, systematically testing samples for antibacterial activity — making the discovery considerably less accidental, and more a matter of a prepared mind recognising the significance of an anomaly it was actively looking for. This card does not adjudicate between these competing accounts, since specialists themselves have not reached consensus; what can be said with confidence is that the tidy "pure luck, single afternoon" version taught in schools compresses and smooths over real uncertainty in the historical record. What is well documented, separately, is that the mould itself likely drifted up from a room below Fleming's, where a colleague's independent mycology work was being conducted — meaning even the most basic "where did the mould come from" element of the story rests on circumstantial, if plausible, later reconstruction (established in 1966) rather than contemporary proof.

A discovery that went almost nowhere for over a decade

What is not in dispute is what happened after the observation: essentially nothing, for more than ten years. Fleming named the substance "penicillin" in March 1929 and presented it to the Medical Research Club in February 1929 under the deliberately modest title "A medium for the isolation of Pfeiffer's bacillus" — a talk that generated no particular interest even from the meeting's own chair, Henry Dale, who later admitted he sensed nothing especially important in it. Fleming's 1929 published paper in the British Journal of Experimental Pathology likewise attracted little attention. His own attempt at clinical application — treating a colleague's sinusitis with penicillin in January 1929 — failed, most likely because the infection was caused by a bacterium penicillin does not kill. Despite working with professional chemists including Harold Raistrick, Fleming and his collaborators found that purifying penicillin into a stable, concentrated, storable form was extraordinarily difficult, and by the mid-1930s the substance had essentially languished. When Fleming presented on penicillin's potential medical significance at an international microbiology congress in 1936, in front of many of the world's leading bacteriologists, his own research assistant V.D. Allison recalled that there was simply no support for the idea and almost no discussion. This decade of near-total neglect is essential to an honest account of the discovery: Fleming identified something real and important in 1928, but identifying it and turning it into medicine were two entirely different scientific problems, and Fleming could only solve the first one.

Florey, Chain, and the Oxford team that made penicillin a medicine

The breakthrough that actually turned penicillin into a usable drug came from an entirely separate research group a decade later. At Oxford, Howard Florey and Ernst Chain — with crucial contributions from Norman Heatley, who devised a practical method for extracting penicillin's active ingredient by manipulating its solubility at different acidity levels, and Edward Abraham, who worked out penicillin's correct chemical structure including its distinctive beta-lactam ring — approached the purification problem systematically from 1939–40 onward, with institutional chemistry resources Fleming had never had access to. Chain's own reaction when Florey told him Fleming wanted to visit the Oxford lab — "Good God! I thought he was dead" — captures just how completely forgotten Fleming and his 1929 paper had become within the scientific community by the time Oxford's work began in earnest. By mid-1942, the Oxford team had produced pure penicillin in usable quantities.

Fleming remained involved and genuinely engaged with the problem throughout this period — his own notebooks show him experimenting with penicillin production methods as late as 1939, and he published a method for assessing penicillin's effectiveness in 1941 — but the decisive chemistry that turned his observation into a drug was Oxford's achievement, not his. As the immunologist Sir Henry Harris later summarised the full chain of dependency: "Without Fleming, no Chain; without Chain, no Florey; without Florey, no Heatley; without Heatley, no penicillin" — a formulation that credits Fleming's foundational observation honestly while making equally clear that four more names, not one, were required to get from laboratory curiosity to medicine.

The case that made Fleming famous — and the myth it created

The moment that brought penicillin, and Fleming personally, to wide public attention came in August 1942, when Harry Lambert — an associate of Fleming's own brother Robert — was admitted to St Mary's Hospital with life-threatening streptococcal meningitis, unresponsive to standard sulphonamide treatment. At Fleming's request, Florey supplied an incompletely purified penicillin sample, which Fleming administered directly into Lambert's spinal canal; Lambert showed improvement within a day and fully recovered within a week. Fleming published the case in The Lancet in 1943, and the story was picked up prominently by The Times and other press. Crucially, Florey — for reasons of scientific caution and a general dislike of publicity — actively kept the Oxford team out of media coverage, while Fleming, at St Mary's in London and readily available to journalists, became the public face of the discovery almost by default. The result was a lasting and significantly distorted popular impression that Fleming alone had both discovered and developed penicillin — a misconception widely reported to have been called "the Fleming Myth" by Fleming himself, who by most accounts remained genuinely and publicly modest about the Oxford team's far greater role in the practical achievement.

This press attention did have one entirely positive and well-documented consequence: it helped prompt direct government action. The British Ministry of Health and War Cabinet moved to accelerate penicillin production, and the UK Penicillin Committee was formally established in April 1943, coordinating British and American manufacturing efforts. By D-Day in June 1944, enough penicillin had been produced to treat every wounded Allied soldier who needed it — arguably the single clearest real-world demonstration of the discovery's ultimate significance.

Recognition, later life, and a warning that proved prophetic

Fleming, Florey, and Chain shared the 1945 Nobel Prize in Physiology or Medicine, and Fleming was knighted in 1944. He remained scientifically active and publicly engaged in his later career, and is notable for one specific piece of foresight that reads as remarkably prescient today: in his June 1945 Nobel lecture, Fleming explicitly warned of the danger of antibiotic resistance emerging from careless use of the very drug he had discovered, stating that a "thoughtless person playing with penicillin is morally responsible for the death of the man who finally succumbs to infection with the penicillin-resistant organism" — a warning that anticipated, with striking accuracy, one of the defining public health challenges of the twenty-first century. His personal life in this period included the death of his first wife, Sarah, in 1949, and his 1953 remarriage to Amalia Koutsouri-Vourekas, a Greek microbiologist and former research colleague at St Mary's.

Death and lasting legacy

Fleming died of a heart attack at his London home on 11 March 1955, aged 73; his ashes are interred at St Paul's Cathedral, a mark of the scale of national recognition he received. His laboratory at St Mary's Hospital is preserved today as the Alexander Fleming Laboratory Museum. In a 2009 Scottish public poll, he was voted the third-greatest Scot in history, behind only Robert Burns and William Wallace — testament to how completely, despite the real complexity of the discovery story, Fleming's name has become permanently and specifically attached to one of medicine's most consequential breakthroughs.

• Before penicillin, Fleming had already made a genuine antibacterial discovery — lysozyme, found in tears and mucus — in 1921, years before the famous mould incident, showing his 1928 breakthrough built on prior, deliberate research rather than being an isolated fluke.
• The precise story of the September 1928 discovery is less certain than the popular version suggests: there is no contemporary record of the exact moment, a roughly two-month gap exists before it appears in Fleming's notebook, and serious historians have proposed at least two competing, more complicated accounts of what actually happened.
• The mould that contaminated Fleming's plate most likely drifted up from a laboratory directly below his, where a colleague was independently conducting mycology research — established only in 1966, decades after the discovery itself.
• Fleming's own first attempt to use penicillin clinically, on a colleague's sinusitis in January 1929, failed — the infection happened to be caused by a bacterium penicillin doesn't kill.
• Penicillin was essentially ignored by the scientific community for over a decade after its discovery; when Fleming presented it at a major international congress in 1936, "no one believed him," according to his own research assistant.
• When Howard Florey told his Oxford colleague Ernst Chain that Fleming wanted to visit their lab in 1940, Chain's reaction was: "Good God! I thought he was dead" — a measure of how forgotten Fleming's 1929 paper had become.
• Fleming became a household name largely because Howard Florey deliberately kept the Oxford team that actually turned penicillin into a working drug out of the press — a decision Fleming himself reportedly called "the Fleming Myth."
• In his 1945 Nobel lecture, Fleming explicitly warned about antibiotic resistance — a problem now recognised as one of the major global health challenges of the twenty-first century, anticipated with striking accuracy nearly 80 years in advance.

The central myth this card addresses head-on is the "pure accident, single dramatic afternoon" version of the September 1928 discovery, which is widely taught but does not fully hold up against the documentary record: there is no contemporary account of the exact moment, a real gap before it enters Fleming's notebook, unresolved scientific questions about how mature bacterial colonies could have been affected by penicillin in the way described, and two distinct, more complicated scholarly reconstructions (Hare, 1970; Root-Bernstein, 1989) that this card presents as genuinely unresolved rather than picking a winner. The second major myth is the "Fleming alone discovered and developed penicillin" impression created by wartime press coverage — corrected here by giving full, specific weight to Florey, Chain, Heatley, and Abraham's essential and much longer scientific effort. Readers should take away that Fleming's 1928 observation was real, important, and built on years of relevant prior research (lysozyme) — but that turning it into the medicine that actually saved millions of lives was substantially someone else's achievement, a decade later.