It is true that we have received accounts from different parts of the country of numerous cases of Smallpox having occurred after Vaccination; and we cannot doubt that the prejudices of the people against this preventive expedient are assignable (and not altogether unreasonably perhaps) to this cause. These cases the Board has been industriously employed in investigating; and though it appears that many of them rest only on hearsay evidence, and that others seem to have undergone the Vaccine Process imperfectly some years since when it was less well understood, and practised less skilfully than it ought to be; yet, after every reasonable deduction, we are compelled to allow that too many still remain on undeniable proof, to leave any doubt that the pretensions of Vaccination to the merit of a perfect and exclusive security in all cases against Smallpox, were admitted at first too unreservedly.
The significance of a confession like the foregoing is not to be estimated literally. It was exacted under irresistible pressure of facts, numerous, definite and undeniable, after every method of excuse and prevarication had been exhausted. In short, it was an authoritative retractation of the flaming medical testimony with which vaccination had been commended to the public in 1800, when the heads of the profession thought it their duty to declare in the newspapers—
That those persons who have had the Cowpox are perfectly secure from the future infection of the Smallpox.
And of Jenner’s emphatic assurance—
That the human frame, when once it has felt the influence of the genuine Cowpox is never afterwards, at any period of its existence, assailable by the Smallpox.
The occasion of Jeffrey’s article was the publication by Dr. John Thomson of a treatise on a violent epidemic in Edinburgh, and other parts of Scotland, in 1818-19.[224] The disease differed from ordinary smallpox in respect of the smallness of the pustules, which contained a milky fluid, and began to dry up on the fourth or fifth day. In Thomson’s words—
The epidemic appeared to exhibit all the varieties of Smallpox from the mildest to the most malignant; and it was curious to observe that the mildest forms, as well as the most malignant, were strictly vesicular eruptions, in which scarcely a trace of purulent matter was to be seen from their commencement to their termination.
Whether this epidemic was smallpox or chickenpox, was the question. It was chickenpox said some. It was modified smallpox said others. It probably was chickenpox said Thomson; and if so, he argued, chickenpox should be accounted a variety of smallpox. The chief cause of uncertainty was, that the vaccinated constituted the majority of sufferers—
Had the unvaccinated alone been attacked [wrote Thomson], nothing, it appears to me, but the most unreasonable scepticism could ever have suggested a doubt of the disease being genuine Smallpox.