The entry says that most of what was said against Jenner’s book went for the chapter he could not prove and left the boy alone. This piece sets out the objections in the order they were made, with each man’s own words, because together they are a fair record of what a careful reader could see from outside the experiment. Four of the five were right about something. None of them was right about the main claim.

Haygarth, August 1796

The first objection was made six weeks after the test on Phipps, by a man who had never heard of it. John Haygarth of Chester had spent years on the smallpox: he had worked out how far its contagion carried, had run a fever ward on those rules, and in 1793 had published a plan for exterminating the disease from Great Britain by isolation and inoculation. He was, on this subject, the most systematic mind in England.

Jenner’s friend Dr Worthington wrote to him about the cowpox. Haygarth answered on 11 August 1796. “Your account of the cow-pox is indeed very marvellous: being so strange a history, and so contradictory to all past observations on this subject, very clear and full evidence will be required to render it credible.”

Then the method. “You say that this whole rare phenomenon is soon to be published; but do not mention whether by yourself or some other medical friend. In either case, I trust that no reliance will be placed upon vulgar stories. The author should admit nothing but what he has proved by his own personal observation, both in the brute and human species. It would be useless to specify the doubts which must be satisfied upon this subject before rational belief can be obtained.”

And the warning. “If a physician should adopt such a doctrine, and much more, if he should publish it upon inadequate evidence, his character would materially suffer in the public opinion of his knowledge and discernment.”

Two of those three paragraphs describe the book Jenner published two years later. He admitted nothing he had not seen; the sixteen casual cases are his own observation of the human species, and the first chapter is the one place where he goes beyond it, on the brute. The third paragraph is the Royal Society’s advice, written down by a friend a year early.

The Royal Society, 1797

Jenner meant the paper for the Philosophical Transactions, which had printed his work on the cuckoo in 1788 and elected him a fellow in 1789. In June 1797 he wrote that Worthington had read a copy and had recommended “my publishing it as a pamphlet instead of sending it to the Royal Society.”

What happened at the Society is known from one passage in Baron’s second volume, placed late and introduced with an apology. “When the subject was laid before the President, Jenner was given to understand, that he should be cautious and prudent; that he had already gained some credit by his communications to the Royal Society, and ought not to risk his reputation by presenting to the learned body anything which appeared so much at variance with established knowledge, and withal so incredible.”

Baron does not claim a formal rejection, and the distinction matters: he writes that “Jenner was deterred from presenting his paper”, which is not the same as the Society refusing it. He did not know “whether Sir Joseph had any secret advisers”, thought “matters were managed somewhat uncourteously”, and declined to bear hard on the men who reasoned that way, since Haygarth had reasoned the same. There is no referee’s report to read, because there was nothing to referee.

Ingenhousz, October 1798

Jan Ingenhousz is remembered now for showing that plants give off oxygen in light. In his own time he was also one of Europe’s most practised inoculators, having variolated members of the imperial family at Vienna and the household of the Grand Duke of Tuscany, and he signed himself Physician to the Emperor and King.

He was staying at Bowood in Wiltshire in the autumn of 1798, read the Inquiry, and did what a good investigator does: he went and asked. He wrote to Jenner on 12 October, privately, to spare him “the disagreeable necessity of entering into a public controversy”.

The first man he spoke to, a practitioner at Calne, sent him to a farmer at Whitley who thirty years before had bought an infected cow at a fair, caught the cowpox from his own dairy “in a very severe way, accompanied with pain, stiffness, and swelling in the axillary glands”, and afterwards, when the sores were dry, had been inoculated for the smallpox. “The disease took place: a great many small-pox came out, and he communicated the infection to his father, who died of it.”

Ingenhousz drew the obvious conclusion: “This being an incontrovertible fact, of which I obtained the knowledge from the very first man to whom I addressed myself, cannot fail to make some impression on your mind, and excite you to inquire farther on the subject, before you venture finally to decide in favour of a doctrine, which may do great mischief should it prove erroneous.” He had heard several more of the same kind. He also reported that the farmer and a farrier both thought the cowpox spread among cows through the air, from the stench of the sick animals, and not from the milkers’ hands or any horse.

Jenner’s reply contains the two sentences that say most about how he held his own result. The first: “Should it appear in the present instance that I have been led into error, fond as I may appear of the offspring of my labours, I had rather strangle it at once than suffer it to exist, and do a public injury.” The second takes the rule he had used on Phipps and makes it a rule for everyone: “I conceive it would be prudent, until further inquiry has thrown every light on the subject which it is capable of receiving, that (like those who were the objects of my experiments) all should be subjected to the test of variolous matter who have been inoculated for the cow-pox.”

His answer to the farmer at Whitley was the doctrine of the spurious cowpox: the man had had one of the other sores, or the true disease in a form that did not affect the constitution. Ingenhousz did not accept it. Baron’s account is that the correspondence grew steadily less friendly until Jenner let it drop.

Pearson, Pennington and Parr, November 1798

George Pearson of St George’s Hospital read the book, wrote to practitioners all over the country, and published their answers within five months. He opened by giving Jenner everything: the honour of the discovery “by the justest title, belongs exclusively to Dr. Jenner; and I would not pluck a sprig of laurel from the wreath that decorates his brow”, and he set out the two central facts as Jenner’s cases established them.

Then he took the first chapter apart. On the origin of the cowpox in the grease of horses’ heels: “this conclusion has no better support, than the coincidence in some instances of the prevalence of the two diseases in the same farm, and in which the same servants are employed among the horses and cows. This assertion stands in need of support from other observations.” He noted, correctly, that the one experiment that would decide it, inoculating a cow’s teats with matter from a horse’s heel, had been tried by Jenner “but without success”.

He had evidence of his own. Sir Isaac Pennington wrote from Cambridge on 14 September 1798 that he had inquired at Cottenham and Willingham, two parishes keeping three thousand milch cows and a great many rough-legged cart horses “much liable to the scratches or grease”, with half the land under the plough and the men much employed in milking: “I cannot find that any pustulous eruptions on the teats of the Cow, or on the hands of the milkers, have ever been heard of; and what seems to prove the negative in this case, I understand inoculation succeeds just as well in these parishes, as any where else.” He added that he could not find that farriers were less liable to the smallpox than other people, which was a direct hit on the three cases of infection from the horse. Pearson himself reported farms where the cowpox broke out although no new animal had come in, although the milkers touched no horses, and although there were no horses on the place at all.

Dr Parr of Exeter was blunter. The assertion that the cowpox proceeds from the heels of horses was “gratuitous”; men rarely milked in his county, and “such insufferable dirtiness as to milk with hands streaming with the running of a sore heel, would not be tolerated in any milking court in this county. Indeed, I think this publication (Dr. Jenner’s) is a libel on his own neighbourhood.”

The grease theory took the heaviest fire in the book’s first year because it was the part of the book that no reader could check and that other readers could contradict from their own districts. Two centuries later it is the part that has worn best: the virus in the vaccine is not the cowpox, and the oldest vaccine stock yet sequenced is closest to the horsepox.

Fewster, October 1798

The strangest objection came from the man best placed to have made the discovery. John Fewster of Thornbury had been inoculating with the Suttons since 1768, and in that year had worked out from a farmer’s offhand remark that the people he could not infect had all had the cowpox. He had told a medical society, and had gone on noticing it for thirty years.

Asked for his opinion in 1798, he wrote to Mr Rolph of Peckham, and Pearson printed the letter. “I can now, with truth, affirm that I have not been able to produce the Smallpox, in a single instance, among persons who have had the true Cowpox,” he wrote; in the course of thirty years and some two thousand inoculations he had never known the cowpox to be fatal or even dangerous. And then: “I think it is a much more severe disease in general than the inoculated Smallpox. I do not see any great advantage from inoculation for the Cowpox. Inoculation for the Smallpox seems to be so well understood, that there is very little need of a substitute.”

The facts and the conclusion sit a sentence apart. Fewster’s objection was not that Jenner was wrong; it was that the thing was not worth doing, because the practice he already had worked well enough. He was comparing the cowpox caught from a cow, which he had seen laying milkers up for days, with the smallpox given by a skilled inoculator, which he had seen go easily two thousand times. What he did not have was Jenner’s observation that the cowpox given by inoculation, from a human arm at the right stage, was slighter than the cowpox caught in a dairy, and that it could not be passed on by air. The comparison he made was the wrong one, and it was the only one his thirty years had prepared him to make.

Goldson, 1804

The last objection is the one that was right, and it was read as the others had been.

William Goldson, a surgeon at Portsea, published in 1804 the cases of children he and others had vaccinated three and four years earlier and had then inoculated with smallpox matter. The Fuller children had been vaccinated in May 1800, April 1803 and March 1804; on 5 June 1804 they were inoculated with the smallpox, and the arms did not read as they should. A girl vaccinated about five years before was inoculated in April 1804 “to try whether time had weakened its prophylactic powers”: her arm inflamed for four days, subsided, and then on about the eighth day “became more florid, and she was attacked with fever, attended with delirium, for several hours”. The title of his pamphlet puts the claim plainly: cases of smallpox subsequent to vaccination.

Jenner’s answer went to the gauge and to the boy. He had, he wrote that year, taken everyone he could find whom he had vaccinated at the start of his practice and exposed them to a woman “covered from head to foot with pustules”: “All have escaped unhurt except at the sight of the ghastly object. A great number of these had been inoculated six years ago. Phipps, too, the boy on whom I made my first trial more than eight years ago, has again been put to the trial with impunity.”

Then he changed the instrument. “I will just remark that the fairest of all tests is exposure to variolous contagion; this is the natural test, inoculation is not. Who does not know (all medical men ought to know) that the insertion of the variolous poison into the skin of an irritable person will sometimes produce great inflammation, disturbance of the system, and even eruptions?”

That is a defensible point about inoculation into an irritable skin. It is also, in 1804, a change in the rule Jenner had written to Ingenhousz in 1798, when the test of variolous matter was the test everyone was to use, because it was the test the whole of Case XVII rested on. Exposure to contagion is a weaker instrument, not a stronger one: it fails to infect some unprotected people too, and it cannot be read on a particular day. Goldson’s children were explained by bad matter and irritable skins, and some of them certainly had been badly vaccinated. Within a generation it was settled that the protection wore off and that revaccination was needed, which is the thing Goldson’s title says.

Moseley, 1805

Benjamin Moseley of the Royal Hospital at Chelsea belongs here for the record rather than the argument. His Treatise on the Lues Bovilla holds that the cowpox gives no security at all, that the whole business is a delusion, and that the proper answer to the smallpox is to inoculate better: “let the same zeal and expence, — but not the same indiscretion — be employed to propagate the Inoculation of Small Pox, as have been for that of the Cow Pox, and we shall hear no more of those terrible computations.” His sentence on vaccination is the one that survives him: “Like a brutal foe to mankind, it treacherously disarms us; leaves us defenceless; lulls us into imaginary security, — and then exposes us to assassination.”

He also picked up, from the Commons evidence, the figure that was the real argument against his own proposal: two physicians had told the committee that “on an average, one person in three hundred die from Small Pox Inoculation”, and one of them that this was the computation “when performed in the best manner”. That was the risk the cowpox removed, and no critic of the vaccine, in those years, produced a death from it.

Sources

• John Baron, The Life of Edward Jenner, M.D., vol. 1, London: Colburn, 1827. Haygarth’s letter of 11 August 1796; Worthington’s advice of June 1797; Ingenhousz’s letter of 12 October 1798, Jenner’s reply and the course of the correspondence; Fewster and the Alveston society; Jenner’s letter of 1804 on Goldson, the exposure of his early patients and Phipps “put to the trial with impunity”. All the letters are quoted here as Baron prints them. archive.org
• John Baron, The Life of Edward Jenner, M.D., vol. 2, London: Colburn, 1838. The Royal Society passage: the advice to the President, “so much at variance with established knowledge, and withal so incredible”, and “Jenner was deterred from presenting his paper”. archive.org
• George Pearson, An Inquiry Concerning the History of the Cowpox, Principally with a View to Supersede and Extinguish the Smallpox, London, 1798. “The justest title” and the sprig of laurel; the two facts as Jenner’s cases establish them; the grease theory’s “no better support” and the failed inoculation of cows’ teats; Sir Isaac Pennington’s letter from Cambridge of 14 September 1798; Dr Parr’s letter from Exeter of 22 July 1798; Fewster’s letter to Rolph of 11 October 1798, printed in full. archive.org
• Edward Jenner, An Inquiry into the Causes and Effects of the Variolæ Vaccinæ, London, 1798, and The Origin of the Vaccine Inoculation, London, 1801. The grease chapter and the admission that it is not proved by experiment; the doctrine of the spurious cowpox and of matter past its stage. gutenberg.org, archive.org
• William Goldson, Some Recent Cases of Small Pox Subsequent to Vaccination, Portsea, 1804. The Fuller children’s vaccination dates and their inoculation on 5 June 1804; the girl inoculated in April 1804 and her fever and delirium. archive.org
• Benjamin Moseley, A Treatise on the Lues Bovilla, or Cow Pox, second edition, London, 1805. “Like a brutal foe to mankind”; the argument for better smallpox inoculation; the one in three hundred, quoted by Moseley from the Commons evidence and so at second hand here. archive.org