The harmlessness of the practice was soon belied—

It gave rise [wrote Birch] to new and painful disorders. It was sometimes followed by itchy eruptions; sometimes by singular ulcerations; and sometimes by glandular swellings of a nature wholly distinct from scrofula, or any other known glandular disease. Eruptions of the skin are most frequent, and may be heard of in every parish of London; and whether Vaccination shall be called the Cow Evil, or the Jennerian Evil, posterity will have to determine.

The non-fatality of the practice was also speedily confuted. The disorders it excited caused numerous deaths—from erysipelas especially. It was then said, as it continues to be said to this day, “Yes, but it was not vaccination, but erysipelas the patient died of”—a form of words that seems to satisfy many minds accounted rational. Birch mentioned three or four cases of death resulting from vaccination, and adds—

These cases were as favourably palliated and ingeniously excused as they could be; but it is admitted that each patient was punctured by a lancet infected with what is called Cowpox; each arm so punctured became inflamed and ulcerated, and each patient died.

The Variolous Test, used so unscrupulously to win converts to vaccination, was proved by the Inoculators to be untrustworthy. They had no difficulty in variolating the vaccinated. When it was discovered that vaccination was no guard against smallpox, many of the vaccinated resorted to inoculation with smallpox, and they “took” as readily as did their unvaccinated acquaintance. Five in one family, the Hignells of Cheltenham, vaccinated by Jenner were variolated by Mr. Freeman, and smallpox resulted in the ordinary course. Nothing indeed became plainer than that the vaunted Variolous Test was a mere conjuring trick, and the more judicious vaccinators ceased to refer to it.

The promise that the vaccinated would remain for ever secure from smallpox Birch had no difficulty with. Londoners vaccinated by the most approved operators caught smallpox, and died precisely as did the unvaccinated. “Every post,” said Birch in 1804, “brings me accounts of the failures of vaccination.” As the failures multiplied, so did the excuses. There was the prime excuse of genuine and spurious cowpox. If vaccination failed, it could only be through the inadvertent use of spurious vaccine. Jenner had taught that one puncture was all-sufficient for protection, but as one was not found effective, it was asserted that two or three were requisite for absolute safety. Many, it was alleged, had been imperfectly operated upon, and the practice of the women and clergy and other busybodies was thrown into discredit, although at the outset their services and testimonies had been blazoned abroad as indisputable; but Birch made this conclusive answer—

It cannot be meant to class Mr. Wachsel, Apothecary to the Smallpox Hospital, or Mr. Bing, the Accoucheur, among ignorant and equivocal practitioners; and yet from the patients vaccinated by these two persons I could bring instance of more failures, more deaths, and more diseases than have occurred in the practice of any other two persons who have come within my knowledge.

Many, moreover, who had been vaccinated by Jenner fell victims to the disease, and he was so pestered with awkward questions, says Birch, “that to avoid the perplexing appeals that were made to him daily, and the messages that were perpetually sent requiring him to visit untoward cases, he retired from London.” Subsequently he had to forsake Cheltenham for the same reason. The convictions of quackery were too numerous for his endurance.

Having proved that vaccination did not prevent smallpox, whilst it was a frequent cause of illness and death, Birch held up to derision the fine promises wherewith its advocates had beguiled the people—

Were an architect to undertake to build an edifice which should be firm in its foundation; all its rooms wind and water tight; and such as might be inhabited with perfect security; if, before the edifice were well finished, the foundations were discovered to be rotten; and if in less than seven years, several apartments had fallen in and killed those who occupied them, while in a great number of rooms, the wind or rain was continually beating in, could I be blamed for declaring that the architect had broken his contract, and that the edifice ought no longer to be inhabited? Certainly not. Why then am I to be told that I am acting perversely when I remonstrate against the practice of Cowpox? for such an edifice as I have described, so rotten in its foundations, so ill built, so ruinous, is Vaccination.