The impression made on Jenner’s mind was simply one of annoyance. He fell back on the assertion that all was not cowpox that was supposed to be cowpox, and that Farmer Stiles could not have had the genuine distemper, or he would not have received smallpox by inoculation. It did not even occur to him that it was necessary to investigate and account for the evidence adduced by Ingenhousz, which was every whit as valid as much of his own. He was content to protest—
In the course of my inquiry, not a single instance occurred of any one having the disease, either casually or from inoculation, who on subsequent exposure to variolous contagion received the infection of smallpox.... 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. At present, I have not the most distant doubt that any person, who has once felt the influence of perfect cowpox matter, would ever be susceptible of that of the smallpox.
Could universal conclusion be deduced from more questionable premisses? and this, too, by one who had just exclaimed, “How very few are capable of conducting physiological experiments!” Always, as we shall see; ungenerous toward those who questioned his assertions, Jenner wrote to his friend, Gardner—
This man, Ingenhousz, knows no more of the real nature of the cowpox than Master Selwyn does of Greek: yet he is among philosophers what Johnson was among the literati, and, by the way, not unlike him in figure—
When, in fact, what provoked him was that Ingenhousz knew too much about cowpox, and had laid his finger on the point of error at the outset. Inquiry on the part of Ingenhousz brought to light several other instances of smallpox after cowpox; and Dr. Pulteney of Blandford reported that Dorsetshire inoculators were familiar with the one sort of pox after the other sort. Jenner’s constant answer to such objections was, “Yes; but it could not have been true cowpox to start with”—a style of argument maintained with parrot-like persistency when smallpox followed vaccination. “Ah!” it was said, “there must have been some mistake about the vaccination; for no one can be thoroughly vaccinated and have smallpox.”
Looking back on the final years of last century, it is much to be regretted that more pains were not taken to hold Jenner fast to his position that smallpox never followed cowpox, and to demonstrate beyond contention that it was not true. It certainly was not true; the evidence to that fact was indisputable; but few were disposed to follow Ingenhousz into the West of England and search for the requisite proof; and Ingenhousz was cut out of the controversy by his death at Bowood on 7th September, 1799. Presently Jenner managed to have the contention shifted from the experience of the dairies to vaccination from arm to arm and the illusory variolous test, and the advantage of a decision at the springs of fallacy was lost. In the general confusion which ensued Jenner came to be taken for a discoverer, and he posed diligently in the character, when he was nothing more than the advertiser of the vulgar opinion of his neighbourhood, with the modification that not Cowpox but Horsegrease Cowpox was the true and infallible specific. The fact is so clear, that he was a mere advertiser, that it would not be worth repetition, were it not so systematically treated as unseen. How distinctly it was at first recognised appears in a letter of thanks for a copy of the Inquiry addressed to Jenner by Francis Knight, a London surgeon, wherein he observed—
Clifford Street, 10th September, 1798.
I have read your publication with much satisfaction; and, from a long residence in the dairy part of Wiltshire, as well as in Gloucestershire, I know the facts to be well supported; at least, it was a general opinion among the dairymen, that those who had received the cowpox were not susceptible of the variolous disease. The cowpox pustule is very familiar to my eye, and I am quite charmed with the delineation of it in your plates. You have opened to the world a very curious field of investigation, and it is too interesting a subject to die with the day.[103]
In these remarks of Knight, we have Jenner’s position accurately defined. He made himself responsible for “the general opinion among the dairymen”; and had some one at that time shown in perspicuous and emphatic fashion that the dairymen were wrong, Jenner would have been summarily disposed of. Vain, however, are such regrets; and we may find comfort in the reflection that there is an order in the universe which converts misfortune into means for greater and rarer good.
Another letter to Jenner from Dr. Hicks contains these remarks—