Then we have a memorandum of Jenner’s, dated 1st April, 1817, wherein he thus traces the course of the virus—
Rise and progress of the equine matter from the farm of Allen at Wansell. From a horse to Allen; from Allen to two or three of his milch cows; from the cows to James Cole, a young man who milked at the farm; from James Cole to John Powell by inoculation from a vesicle on the hand of Cole; and to Anne Powell, an infant; from Powell to Samuel Rudder; from Rudder to Sophia Orpin, and to Henry Martin; from H. Martin to Elizabeth Martin. All this went on with perfect regularity for eight months, when the virus became intermixed with other matter, so that no journal was kept afterwards. Proof was obtained of the patients being duly protected[152]—
Which was to say, that they were subsequently inoculated with Smallpox without effect. Among Jenner’s papers, there were other entries to the same purpose, thus—
17th May, 1817.—Took matter from Jane King (equine direct) for the National Vaccine Establishment. The pustules beautifully correct.[153]
This equine virus from Jane King was extensively diffused. It was, we see, sent to London; it was also sent to Edinburgh;[154] and Dr. Baron says he had supplies of it for use in the Gloucester Infirmary. Baron relates that in the following year he was able to return the gift, having obtained virus from the hands of a boy infected directly from the horse. Here is Jenner’s acknowledgment of the present, dated 25th April, 1818—
My Dear Baron,—Yesterday H. Shrapnell brought me the equine virus and your drawing, which conveys so good an idea of the disease, that no one who has seen it can doubt that the vesicles contain the true and genuine life-preserving fluid. I have inserted some of it into a child’s arm; but I shall be vexed if some of your young men at the Infirmary have not done the same with the fluid fresh from the boy’s hand.[155]
It is surely unnecessary to adduce further evidence of what was Jenner’s mature faith and deliberate practice. Further, it is manifest that to the end of his career he held that pox in the cow was not only derived from grease in the horse, but that it was exclusively derived from the horse, and, that apart from the horse, Cowpox would cease to exist. Owing to the multiplication of vaccination failures, it began to be conjectured that vaccine might be worn out by transmission from arm-to-arm, and that a reversion to the cow might be expedient; and discussing the question in a letter to Moore, dated 5th March, 1816, Jenner advanced the objection—
If there were a real necessity for a renovation, I know not what we should do; for the precautions of the farmers with respect to their horses have driven the Cowpox from their herds.[156]
Why did not Moore rejoin, Where is the difficulty? Suppose pox driven from the herds, what conceivable reason was there for anxiety when the cow had become a demonstrated superfluity?—when, in Jenner’s own words, “the true and genuine life-preserving fluid” might be drawn direct from horses’ heels? Except for the perpetuation of imposture, the cow in the case had ceased to have any value whatever. But, as so often happens with quacks, their minds become so saturated with their own humbug that there is nothing left of common-sense.
Having thus proved my assertions concerning Jenner, it may be reasonably asked, How was it that some got Cowpox by means of Horsegrease when others could not? for, it may be argued, that if Cowpox issued straight and invariably from inoculated Horsegrease, not even the most resolute prejudice against Horsegrease could have permanently kept back the truth.