Notwithstanding these confirmations and his boast that the opposition of Pearson and Woodville was silenced for ever, Jenner suffered judgment to go against him. He recognised that it was expedient that the connection between Horsegrease and Cowpox should be denied. He had his bill to settle with the English public, and it was not for him to make difficulties. A curious evidence of how thoroughly the unpopular truth was suppressed is furnished by Dr. Willan’s treatise _On Vaccine Inoculation_, published in 1806. There is not a word or hint in it concerning Horsegrease. The treatise was the work of a competent physician, who set forth what was known of vaccination (from the standpoint of belief) with fulness and clearness, accompanied with an appendix of letters and reports from Jenner himself, from Pearson and other experts in the new practice--but as to Horsegrease, the silence was absolute. How the disagreeable truth was so effectually covered up is more than I can account for. It was not mentioned in the debates in Parliament, nor was it referred to in the reports of the Colleges of Physicians and Surgeons, nor did the opponents of vaccination use it with the force that might have been expected. One explanation is, that Jenner’s _Inquiry_ never entered into general circulation, that no popular edition ever appeared, and that it was chiefly known at second hand. The leading representatives of vaccination, moreover, so boldly disowned Horsegrease and Jenner’s authority in ascribing Cowpox to its parentage, that there was little use in charging them with it; whilst all the while Jenner offered no open resistance to those who contemned him for one mistake, but exhausted the language of adulation on his imputed merit. Thus we suppose it came to pass that at the end of twenty years Dr. Mason Good, as the exponent of orthodox medical faith, felt justified in asserting that there was no foundation for the opinion that Cowpox originated in Horsegrease, nor that any connection existed between the diseases, and that it was fortunate for Jenner and the triumph of his discovery that the fact was so. Jenner was silenced, but was he convinced? How could he be convinced? Horsegrease as the origin of Cowpox might be voted detestable and impossible, but there was the evidence of the country folk, confirmed by Tanner, Loy, Sacco, De Carro, and La Font; and though a weak man may be put down, or think it worth while to be accounted mistaken, yet, in the stillness of his mind, he knows that facts are facts whatever may be said to the contrary. When, therefore, Jenner had filled his purse, obtaining all he could expect from public favour, and was clear of London, and the oppression of its savants, he reverted to his first opinion as true--true and untrue, true with a distinction, which I shall presently define. Writing to James Moore, Director of the National Vaccine Establishment, from Berkeley, on 23rd July, 1813, he observed--