Which is exactly what any perspicacious reader would infer from the cases adduced in the Inquiry. They were Jenner’s best and his all. Meanwhile, as observed, he had been able to do little in extension of the Inquiry; but if idle and helpless, Dr. Pearson had been active—
Since then Dr. George Pearson has established an inquiry into the validity of my principal assertion, the result of which cannot but be highly flattering to my feelings. It contains [Pearson’s Inquiry] not a single case which I think can be called an exception to the fact I was so firmly impressed with—that the Cowpox protects the human body from the Smallpox. (P. 70.)
Here we have a distinct mis-statement. It was not Jenner’s “fact” that Cowpox protected the human body from Smallpox—that was a widespread superstition. His contribution to the question was a definition of the Cowpox effective against Smallpox, namely Horsegrease Cowpox, other Cowpox being adjudged spurious. Pearson so far from confirming Jenner’s position, deliberately set it aside. He not only accepted the rural faith in Cowpox (which Jenner knew to be unwarrantable), but, when he proceeded to practice, made use of Cowpox which owed nothing to Horsegrease. If therefore Pearson’s procedure was “highly flattering” to Jenner’s feelings, he was either easily pleased, or an adept in dissimulation.
The truth is, the publication of Further Observations was designed by Jenner to loosen himself from what was definite in the Inquiry, so that he might be able to appropriate whatever might result from the investigations and experiments then going on. He had defined prophylactic Cowpox as Horsegrease Cowpox, but Horsegrease did not meet with favour, nor appear likely to answer; and it might be expedient to drop it; and thus he described the ground of his attachment to that form of specific—
Firstly.—I conceived that Horsegrease was the source of Cowpox from observing that where the Cowpox had appeared among the dairies here [Berkeley] (unless it could be traced to the introduction of an infected cow or servant) it had been preceded at the farm by a Horse diseased in the manner described, which Horse had been attended by some of the milkers.
Secondly.—From its being a popular opinion throughout this great dairy country, and from its being insisted on by those who here attend sick cattle.
Thirdly.—From the total absence of the disease in those countries where the men servants are not employed in the dairies.
Fourthly.—From having observed that morbid matter generated by the Horse frequently communicates, in a casual way, a disease to the human subject so like the Cowpox, that in many cases it would be difficult to make the distinction between one and the other.
Fifthly.—From being induced to suppose from experiments, that some of those who had been thus affected from the Horse resisted the Smallpox.
Sixthly.—From the progress and general appearance of the pustule on the arm of the boy whom I inoculated with matter taken from the hand of a man infected by a Horse; and from the similarity to the Cowpox of the general constitutional symptoms which followed. (P. 91.)