In 1782 was employed in dressing the sore heels of Horses, and at the same time assisted in milking Cows, thereby infecting them and generating Smallpox. Changing his situation, he communicated the disease to other Cows, and was himself severely affected. Some years afterwards, he was inoculated with Smallpox by Jenner without effect.
In 1782 had Cowpox severely on the same farm with Nichols. In 1792 he was inoculated with Smallpox along with a large party, but in his case without result. “During the sickening of some of his companions, their symptoms so strongly recalled to his mind his own state when sickening with the Cowpox, that he very pertinently remarked their striking similarity.”
In 1782 had Cowpox when she was attended by Jenner. In 1795 she, and seven other pauper women of Tortsworth, who also had had Cowpox, were inoculated with Smallpox by Henry Jenner without effect. “This state of security proved a fortunate circumstance,” observed Jenner, “as many of the poor women were at the same time in a state of pregnancy.” Why then, it might have been asked, did Henry Jenner try to variolate them?
These Twelve Cases illustrate Jenner’s procedure; and those familiar with scientific methods, and the scrutiny and caution requisite to arrive at trustworthy physiological data, will view with some astonishment his free and easy induction. In the majority of the Cases he was without proof that his subjects had suffered Cowpox; and the absence of this certainty was the more remarkable as he knew that the dairy-folk described as Cowpox several varieties of eruption. The same rural observers who held that Cowpox averted Smallpox, also held that Smallpox averted Cowpox; and yet Jenner had to show in Rodway’s Case No. vii., that they were mistaken; although, granting the thesis that Smallpox and Cowpox were equivalents and mutually preventive, the rural faith ought to have stood justified, and Smallpox shown to be good against Cowpox. Again Jenner allowed that an attack of Cowpox did not prevent a subsequent attack of Cowpox, saying--
It is singular to observe that the Cowpox virus, although it renders the constitution insusceptible of the variolous, should nevertheless leave it unchanged with respect to its own action.