The entry says that when Jenner’s practice reached London it was carried on by other men, in a building full of the disease it was meant to prevent, and that nobody could afterwards say what the first two thousand Londoners had been given. This piece follows those four months through the letters the men wrote to each other at the time, as John Baron printed them in 1827, and through William Woodville’s own published report of May 1799. The quotations from the letters are at second hand through Baron; Woodville’s report and George Pearson’s evidence to the House of Commons are quoted from the printed originals.

The cowshed

On Sunday 20 January 1799 Woodville, physician to the Smallpox Hospital at St Pancras and the author of a history of inoculation, was told that the cowpox had broken out among the cows of a dairy in Gray’s Inn Lane. He wrote the story to Jenner five days later.

“The next day I took Mr. Tanner with me to examine them; and as he declared it to be the genuine disease, I that day inoculated six persons with the matter that he procured from a cow which appeared to be the most severely affected with this pustular complaint.” Tanner was a friend of Jenner’s and had seen the disease in the country. Woodville’s printed report says seven persons, not six, inoculated on Monday 21 January “by a single puncture, in the arm of each, or rather by scratching the skin with the point of the lancet, till the instrument became tinged with blood.”

The dairy kept about two hundred cows, and in the end “about four-fifths of them were eventually infected”; those not in milk escaped. Three or four of the milkers caught sores. One of them, Sarah Rice, had “a more beautiful specimen of the disease than that which you have represented in the first plate”, Woodville told Jenner, and he took matter from her hand, noting that it differed from the cow’s: hers “purely lymphatic”, the cow’s “of a purulent form”. With the matter from her hand he inoculated two men at the hospital.

“Finding now there could be no doubt of the disease,” he went on, “I the same day called upon Sir Joseph Banks, Dr. Pearson, Dr. Willan, &c. to inform them of the circumstance; and these gentlemen, together with Lord Somerville, Sir William Watson, and Mr. Coleman, met me the following day at the cow-keeper’s, where your book was produced; and upon comparing your figure with the disease it was allowed by all to be a very faithful representation, and every gentleman seemed highly gratified at seeing so good an example of the cow-pox.” That was Thursday 24 January by Woodville’s printed account, Friday 25 January by the letter; the two differ by a day. The President of the Royal Society, who eighteen months earlier had advised Jenner that his paper was too incredible for the Philosophical Transactions, stood in a London cowshed with the book open at Plate I.

The precaution that spoiled it

Woodville’s patients were in the Smallpox Hospital, and many of them, he wrote, “were so circumstanced as to be afterwards constantly exposed to the infection of the Small-pox.” He had Jenner’s book but not Jenner’s confidence in it. “Having then had no proof that the progress of the infection of the former would supersede that of the latter, I used the precaution to inoculate the patients with variolous matter on the fifth day after that taken from the cow had been inserted.”

He then carried the cowpox on from the arms of those same patients into the next set.

Jenner, answering by return of post, saw the danger in the exposure if not yet in the method. He suggested “the immediate propriety of inoculating those who may resist the action of the cow-pox matter, and may have been exposed to variolous contagion at the hospital”, and added a piece of practical advice from the dairies: it would “imitate the casual mode more closely were we first by scratch or puncture to create a little scab, and then, removing it, apply the virus on the abraded part.”

The eruptions

The Inquiry says that in the cowpox “no pustules appear”. Woodville’s patients came out in them. By his own count, “the number of cases of Cow-pox, inoculated under my direction, have amounted to about 600”; three-fifths had eruptions on the body, some a few, some a great many. The worst was Ann Bumpus, with 310, “all of which suppurated”.

Pearson wrote to Jenner on 15 February, in a letter whose astonishment is undisguised. “You will be astonished at our talking of eruptions, but it now appears in Dr. Woodville’s cases that as many have eruptions on the body as have them only in the parts inoculated.” He had inoculated a child of about fourteen months in one arm with matter from one of Woodville’s patients and in the other with matter from the cow: “To my astonishment the disorder proceeded exactly as the inoculated small-pox. On the ninth day convulsive fits came on, and vomiting occurred, with other pretty violent symptoms, which alarmed me and made me very uneasy.” And then the suspicion, stated plainly: “I could not persuade myself but that there was some mistake, and that Dr. Woodville’s lancet, which I used, had variolous matter upon it. I called him to see the patient. He assured me the lancet having been lately ground had not been used.”

The lancets were Woodville’s own defence, and he printed it. When he first saw a pustular eruption on one of his patients he had been “not without apprehension that the lancet which was employed in his inoculation might have had some particles of variolous matter adhering to it. But this suspicion was soon removed; for, upon enquiry, I found that all the lancets which I had used on the 21st of January, were then made use of for the first time since they had been ground by the cutler.”

The lancets of 21 January were clean. What he does not treat as a difficulty is what he had done on the twenty-sixth, and what he did thereafter with matter from arms that carried both diseases. He argued the point out and dismissed it: because the cowpox matter was always taken before the smallpox inoculation could affect the constitution, “I apprehend its effects would be the same as if the variolous inoculation had not taken place.” He also reported an experiment of his own that tells more than he meant it to. “Twenty-eight patients were on the same day inoculated with the matter of Cow-pox, and that of the Small-pox, mixed together in equal quantities, in order to try which would prevail, or if it were possible to produce a hybrid disease by a union of both.” In more than half, he wrote, the local sore took the character of the cowpox; in the rest it looked more like the smallpox.

Jenner’s reading, which he came to within weeks, was that the London matter had been contaminated. The word offended Woodville. It was, as Baron wrote, “the only one that was really expressive of the fact”. Baron adds an anecdote of the hospital from a source he trusted: a medical gentleman charging threads with lymph to send to correspondents round the country, and the apothecary, Wachsel, returning to the room to find him taking it from a patient covered in smallpox pustules. “Then, Sir, you know not what you are doing, you are taking the virus of small pox.”

What went out

The stock did not stay in London. Pearson told the House of Commons in 1802 that within a few months he had “issued a printed letter, directed to upwards of 200 practitioners in different parts of the kingdom, containing thread impregnated with cow-pox matter”, and that by August 1799, between Woodville’s cases and his own correspondents, “2000 cases had by that time been afforded to the public”.

A surgeon named Jordan told the same committee what that could mean. He had been inoculating with vaccine matter for two or three years, from the apothecary at the hospital where Woodville presided. Asked whether he had ever had a mistake about the quality of the matter sent to him, he answered: “Matter was inserted by me, sent from thence, which proved to be variolous.” His patients did well, “but not being sufficiently guarded against, I had every reason to think the cases would have proved fatal.” Since then, he said, he armed his own lancets from the patient himself.

Woodville also sent a thread to Jenner in Gloucestershire, charged from the arm of Ann Bumpus, the girl with the 310 pustules. Jenner inoculated twenty people with it, and another surgeon in the county 140, and Woodville printed the result: it produced no pustules that maturated. Jenner reported back that “the rise, progress, and termination of the pustule, created by this virus on the arm, was exactly that of the true uncontaminated Cow-pox.” Two of the children Jenner inoculated from the London thread were his own son Stephen, three and a half, and a boy named James Hill, four; Stephen had a few vivid red spots on his arms and face that faded without maturating, and both were afterwards exposed to the smallpox without effect.

Passed through a few country arms, in other words, the thing from the Smallpox Hospital behaved like the thing from Berkeley again. Jenner explained the difference at first by the air of London, and Woodville answered that several of his cases had been inoculated eight miles out of town, and eighteen more in a village further still, all of whom had pustules. Neither explanation was right, and neither man could settle it, because the one thing that would have settled it, a sample of the matter as it stood on each day, could not be kept.

What the London year proved

Set against all that, Woodville’s figures were the strongest evidence anyone had produced. Of his patients, “upwards of 400” were afterwards inoculated with smallpox matter, and “none were affected with the Small-pox”; nearly a quarter of them had gone through the cowpox so slightly that it “neither produced any perceptible indisposition, nor pustules”, and even those resisted. He stated the conclusion as a law: it “appears to be as much a general law of the system, as that a person having had the Small-pox is thereby rendered unsusceptible of receiving the disease a second time.”

The trouble is in the pairing. The four hundred are the best test of Jenner’s claim made in its first year, and they were made with a stock that for part of that year was, by the strongest evidence available then and since, partly the smallpox. If the matter was contaminated, then some of those four hundred were protected by the disease the trial was meant to replace, and the trial proved what nobody doubted. If it was not, Jenner’s description of the cowpox was wrong in one of its particulars. Both readings cannot be true, and nothing in the trial could tell them apart.

Woodville, in May 1799, still thought the eruptions belonged to the cowpox and that the question remained open; within the year he had come round to Jenner’s view. What neither of them could do was go back and look. The lancets had been cleaned, the threads had gone out to two hundred practitioners, and the matter had moved on into other arms.

Sources

• William Woodville, Reports of a Series of Inoculations for the Variolæ Vaccinæ, or Cow-Pox; with Remarks and Observations on This Disease, Considered as a Substitute for the Small-Pox, London: James Phillips, 1799. The dairy and its two hundred cows; Sarah Rice; the gathering of 24 January; the seven inoculated on 21 January and the method; the smallpox matter on the fifth day; the lancets from the cutler; the twenty-eight mixed inoculations; Ann Bumpus’s stock sent to Gloucestershire and Jenner’s report of it; the patients inoculated eight miles from London; “about 600” inoculated and “upwards of 400” tested; the general law. archive.org
• John Baron, The Life of Edward Jenner, M.D., vol. 1, London: Colburn, 1827, chapter on the year 1799. Woodville’s letter of 25 January 1799 and Jenner’s reply; Pearson’s letter of 15 February 1799; the three-fifths; “contaminated”; the Wachsel anecdote. All the letters in this piece are quoted as Baron prints them. archive.org
• Edward Jenner, Further Observations on the Variolæ Vaccinæ, or Cow Pox, London, 1799. The two children inoculated with the London thread, Stephen Jenner and James Hill, day by day; the eighteen at Eastington; the air of London. archive.org
• The Evidence at Large, as Laid before the Committee of the House of Commons, Respecting Dr. Jenner’s Discovery of Vaccine Inoculation, London, 1805. Pearson on the printed letter to upwards of 200 practitioners and the 2,000 cases; Mr Jordan on matter that “proved to be variolous”. archive.org