Edward Jenner

Edward Jenner (1749—1823) was an English physician and naturalist who introduced vaccination against smallpox in 1798, deriving the technique from folk knowledge that cowpox infection conferred immunity. His Inquiry into the Causes and Effects of the Variolae Vaccinae launched a practice that eventually led to the eradication of smallpox, the only human disease to have been deliberately eliminated. Yet the history of vaccination is considerably more contested than Jenner’s heroic reputation suggests. His original theoretical framework — that cowpox derived from horsepox (“the grease”) and was itself a mild form of smallpox — was wrong, his early evidence was thin and selectively presented, and his priority over earlier vaccinators was maintained partly through suppression.

Life and Context

Jenner’s early experience of smallpox inoculation at age eight — six weeks of preparatory bleeding, purging, and low diet followed by confinement in “a terrible state of disease” in an inoculation stable — may have motivated his later work to replace variolation with a safer alternative (Crookshank, Edgar M., 1889). John Hunter mentored Jenner as a house pupil, and Jenner later communicated his observations on tartar emetic and the cuckoo to Hunter; Hunter’s letters to Jenner, rediscovered at the Royal College of Surgeons Library in 1888, are key primary sources for this relationship (Crookshank, Edgar M., 1889).

In 1780, Jenner articulated his theory in conversation with Edward Gardner: that cowpox derived from horsepox (“the grease”), and that vaccination could be disseminated “all over the globe to the total extinction of Small Pox” — but he kept it private to avoid ridicule if experiments failed (Crookshank, Edgar M., 1889). Crookshank discovered at the Royal College of Surgeons Library a manuscript that was Jenner’s original communication to the Royal Society — differing substantially from the published Inquiry — which had lain in a drawer unnoticed since 1879 (Crookshank, Edgar M., 1889).

Jenner was born on 17 May 1749 in Berkeley, Gloucestershire, the fifth son of the Reverend Stephen Jenner, and at age eight was variolated – an experience he remembered bitterly for life.(Bazin, 2000) At thirteen he was apprenticed to surgeon John Ludlow of Chipping Sodbury for six years, then went to London to board with the celebrated surgeon John Hunter.(Bazin, 2000) It was in London that Jenner formed lasting friendships with Henry Cline and Everard Home.(Bazin, 2000) He published his first book on vaccination in September 1798 at his own expense – a concise 75‑page volume with four colour engravings, sold at seven shillings and sixpence from two London bookshops.(Bazin, 2000)

Core Contributions

Precursors and Priority

The dairymaid tradition — that cowpox conferred immunity to smallpox — arose specifically from the failure of variolation to “take” in persons who had previously contracted cowpox, not from ancient folk knowledge predating inoculation (Crookshank, Edgar M., 1889). Benjamin Jesty, a farmer of Yetminster, Dorset, deliberately inoculated his wife and two sons with fresh cowpox matter in 1774 — the earliest documented intentional vaccination, predating Jenner by twenty-four years (Crookshank, Edgar M., 1889). Fifteen years later, Jesty’s sons were challenged by inoculation with variolous matter and showed only local inflammation with no fever or eruption, confirming lasting immunity (Crookshank, Edgar M., 1889). Jenner dismissed Jesty’s prior vaccination as a “trick” invented by George Pearson to deprive him of credit, while Baron’s biography of Jenner virtually ignored Jesty’s documented vaccinations (Crookshank, Edgar M., 1889).

Benjamin Jesty, a farmer of the Isle of Purbeck, inoculated his wife and two sons with cowpox in 1774, and they were subsequently found unsusceptible to smallpox (Crookshank, Edgar M., 1889).

The Inquiry and Its Evidence

Jenner’s original manuscript for the Royal Society (the “Rejected Inquiry,” presented c. 1796—97) opened with the hypothesis that human infectious fevers arise from familiarization with animals, and specifically argued that horsepox transmitted to cows was the origin of cowpox (Crookshank, Edgar M., 1889). It presented only ten cowpox cases as evidence for immunity, selected specifically as instances where smallpox inoculation failed; no cases of successful re-inoculation after cowpox were included (Crookshank, Edgar M., 1889).

The first recorded deliberate vaccination experiment by Jenner was on 14 May 1796: he inoculated James Phipps, a healthy boy about eight years old, with cowpox matter from the dairymaid Sarah Nelmes; the boy was mildly ill on days seven through nine and well on day ten.(Crookshank, Edgar M., 1889)(Bazin, 2000) The variolous challenge test was applied less than seven weeks later and produced no disease — though Crookshank notes that this very short interval was a weakness in the evidence (Crookshank, Edgar M., 1889).

Jenner’s three “grease” (horsepox) cases showed contradictory results: one subject resisted inoculation, another had eruptions, and a third contracted natural smallpox — findings that undermined his horsepox-origin theory (Crookshank, Edgar M., 1889). William Smith’s case — cowpox contracted in 1780, 1791, and 1794 with equal severity each time — directly contradicted the theory that a single attack of cowpox conferred lasting immunity, yet Jenner included the case without explanation (Crookshank, Edgar M., 1889).

Between the rejected manuscript and the published Inquiry (1798), Jenner added new cases and re-inoculated Phipps, strengthening the evidence base before publication as a pamphlet (Crookshank, Edgar M., 1889). John Baker, a five-year-old boy inoculated by Jenner with horsepox matter in March 1798, developed a pustule and subsequently died — a death Jenner suppressed in the published Inquiry, attributing it to “a contagious fever” caught in a workhouse (Crookshank, Edgar M., 1889). Jenner tried to procure horse-grease virus before publication, going so far as to keep a horse on beans to make its heels swell, but all attempts failed (Crookshank, Edgar M., 1889).

The published Inquiry introduced the concept of “spurious cowpox” as a category to explain cases where cowpox infection did not confer immunity — creating a built-in explanation for failures that made the vaccine theory effectively non-falsifiable (Crookshank, Edgar M., 1889). Jenner believed cowpox and smallpox were modifications of the same disease (“variolae vaccinae”), both derived from “grease” — which became smallpox when passed through humans and cowpox when passed through cattle (Crookshank, Edgar M., 1889).

Early Reception

After Jenner’s initial publication, Henry Cline’s August 1798 vaccination trial in London succeeded: the child sickened on day seven, recovered by day eleven, and subsequent challenge produced no disease — Cline called it “one of the greatest improvements that has ever been made in medicine” (Crookshank, Edgar M., 1889). But Woodville at the Smallpox Hospital vaccinated extensively in a variolous atmosphere, producing cases where cowpox and smallpox occurred simultaneously (Crookshank, Edgar M., 1889). Crookshank argued that Jenner consciously avoided practicing in London after publishing the Inquiry because he feared rigorous challenge testing would expose failures in his theory (Crookshank, Edgar M., 1889).

Reception and Legacy

Jenner’s vaccination against smallpox (1796) — derived from folk knowledge that cowpox conferred immunity — was the one eighteenth-century improvement that decisively saved lives on a large scale (Porter, 1997). The experiment: Jenner inoculated cowpox material from a milkmaid into a boy, who developed a local scab and mild fever, and six weeks later the boy showed no smallpox after a challenge inoculation with smallpox matter (Bynum, 1994)(George Rosen, 1993). Jenner’s paper was initially rejected by the Royal Society, prompting him to publish independently in 1798 as An Inquiry into the Causes and Effects of the Variolae Vaccinae (George Rosen, 1993). The practice spread rapidly: by 1801, at least 100,000 persons had been vaccinated in England alone, and within a few years the Inquiry had been translated into the principal European languages (George Rosen, 1993).

The published Inquiry explicitly argued that horse-grease passed through the cow became cowpox, while horse-grease inoculated directly into humans did not reliably confer immunity (Crookshank, Edgar M., 1889). Jenner acknowledged this theory required further experimental proof he had not yet obtained (Crookshank, Edgar M., 1889). Crookshank’s investigation of vaccination originated from a 1887 cowpox outbreak in which he proved the cows had not been infected by milkers suffering from smallpox, contradicting commonly accepted doctrines (Crookshank, Edgar M., 1889).

Parliamentary Rewards

Jenner appealed to the British House of Commons for a grant on 17 March 1802, pointing out that all the world had benefited from his discovery except himself. After prolonged debate, a subsidy of £10,000 was voted by a small majority, with a £20,000 proposal failing narrowly; Bazin’s source Fischer (1991) estimated £10,000 in 1802 to be equivalent to approximately £1 million at 1990 values.(Bazin, 2000) A second, more substantial grant followed in 1807, after the Royal College of Physicians undertook a lengthy inquiry — including investigation of Jenner’s personal morality and competence — and on 10 April 1807 issued a report strongly and without reservation recommending Jennerian vaccination. The government voted £20,000, carried 60 to 47.(Bazin, 2000)

Jenner vaccinated anyone who wanted it free of charge. His free Thursday-morning sessions in Cheltenham attracted crowds of up to 400, making his neighbours hostile enough to rename his house “that Pest House.” At Berkeley, a shed in a corner of his garden became known as the Temple of Vaccinia and served as his primary free clinic.(Bazin, 2000) The Royal Jennerian Society for the Extermination of Smallpox was founded in London on 17 February 1803; within eighteen months it vaccinated 12,288 people and dispatched 19,352 vaccine doses within Great Britain and abroad.(Bazin, 2000)

During the Napoleonic wars, Jenner wrote personally to the Institute of France and to Napoleon on behalf of English prisoners of war, and the French reportedly freed at least two of his protégés at his request; Napoleon is attributed the remark “Jenner — we can’t refuse that man anything,” though Bazin qualifies the attribution as “is supposed to have said.”(Bazin, 2000)

Global Diffusion

In 1803, Charles IV, the Bourbon King of Spain — who had lost a child to smallpox — sponsored an extraordinary expedition led by Francisco Xavier de Balmis throughout the Spanish Empire; because there was no means of preserving the vaccine, it was administered live, arm-to-arm, carried in the bodies of twenty-one Spanish orphans vaccinated in succession.(Jackson (ed.), 2011) On 30 November 1803, a task force left La Coruña for the Canary Islands, then to Puerto Rico.(Bazin, 2000) From Puerto Rico, some of the expedition proceeded to South America while the rest continued to Havana and Mexico.(Bazin, 2000) The expedition then went from Acapulco to the Philippines, Macao, and Canton.(Bazin, 2000) Live smallpox vaccine was preserved by using a chain of orphaned children vaccinated one after another.(Bazin, 2000)

Vaccine had already reached India by a different route: the Vienna physician John De Carro supplied material of Italian origin that travelled via Constantinople to Baghdad, Bassora, and finally to Bombay, where the first vaccination was performed on Anna Dusthill on 14 June 1802.(Bazin, 2000) From Bombay the vaccine reached Ceylon by 11 August 1802. In North America, Thomas Jefferson became a fervent advocate, vaccinating his own family and cousins and distributing vaccine to Native American tribes; Jenner later maintained direct correspondence with indigenous Canadian communities who congratulated him on the discovery.(Bazin, 2000) In France, the Comité Central de Vaccine conducted systematic trials from June 1800 onwards, vaccinating children in maternity hospitals, orphanages, prisons, and colonial institutions, including among enslaved people.(Bazin, 2000)

Later Life and Death

Jenner died on the morning of 26 January 1823 in Berkeley after suffering a stroke in his library the previous day; his servant found him unconscious on the floor. His friends in London proposed a public funeral with burial at Westminster Abbey, which the Government accepted on the condition that the family bear the costs. The family declined — they could not afford it — and Jenner was buried on 3 February 1823 beside his wife in the chancel of Berkeley church.(Bazin, 2000)

Even George Pearson, Jenner’s most determined institutional rival, later admitted before the British House of Commons that Jenner had not known of prior cowpox inoculation trials, and that Jenner was the first to inoculate vaccinal material from person to person — thereby permitting for the first time the storage of a viable vaccine stock.(Bazin, 2000) Bazin’s own assessment situates Jenner within the moral framework of his period: the variolation challenges performed on vaccinated subjects were standard contemporary practice carried out by hundreds of physicians worldwide without ethical objection, and nothing in the documented record indicates that Jenner transgressed the norms of his time.(Bazin, 2000)

Fleck’s Genesis and Development of a Scientific Fact (1935) is in the Library with 5 chapters extracted, but its case study is the Wassermann reaction for syphilis, not vaccination; Jenner appears only in passing as a precursor figure. Fleck’s general epistemological concepts — thought-style, proto-ideas, active/passive associations — could be applied to the vaccination story interpretively, but the extracted chapters do not constitute sourced evidence for Jenner specifically.

See Also

• Vaccination
• Smallpox
• Variolation
• Benjamin Jesty
• John Hunter
• Louis Pasteur
• Anti-Vaccination Movement

Sources

All claims cite evidence cards from:

• Crookshank, E.M. (1889). History and Pathology of Vaccination. 2 vols. London: H.K. Lewis. [Source ID: crookshank-historyvaccination-1889]
• Bynum, W.F. (1994). Science and the Practice of Medicine in the Nineteenth Century. Cambridge: Cambridge University Press. [Source ID: bynum-sciencepractice-1994]
• Porter, R. (1997). The Greatest Benefit to Mankind. London: HarperCollins. [Source ID: porter-greatestbenefit-1997]
• Rosen, George. (1993). A History of Public Health. Expanded ed. Baltimore: Johns Hopkins University Press. [Source ID: rosen-historypublichealth-1993, ch05]
• Bazin, H. (2000). The Eradication of Smallpox. Academic Press. [Source ID: bazin-eradication-of-smallpox-2000]