I published experiments of inoculating persons with the Cowpock to show that _they could not take the Cowpock after the Smallpox_, contrary to Dr. Jenner. Secondly, experiments to show that persons could not take the Cowpock who had already gone through the Cowpock, also contrary to Dr. Jenner.[129] Thirdly, many persons had at this period made experiments to show that _the Cowpox did not originate in the grease of Horses’ heels_, as Dr. Jenner had asserted. In the spring of 1799, a second publication appeared from Dr. Jenner recommending caustic or escharotics to the inoculated parts in Cowpox, which we found wholly unnecessary in practice; and I consider that the distinctive characters of the Cowpock were better understood by some of us than by Dr. Jenner himself. One can only say of these statements of Pearson as against Jenner, that they are simple matters of fact, impugn them whoso list. It is impossible to controvert Pearson’s assertion-- That the whole of Jenner’s experience extended to seven or eight cases, and a part only of these--namely, four--were from human subject to human subject; and not until long after Dr. Woodville and myself had published several hundred instances of vaccine virus transmitted from arm to arm, had he any experiments to set alongside ours. They had to find out for themselves when to take virus from the cow, how to preserve it when taken, how to dress inoculated arms, when to take virus from the arm, and, in short, to do everything that constitutes the difference between a suggestion and an art. Pearson, too, as we have seen, had a leading part in the formation of the first Institution for the Inoculation of the Vaccine Pock, with which Jenner had not only nothing to do, but _would_ have nothing to do: concerning which wrote Pearson-- The Vaccine Inoculation was next considerably established by the Cowpock Institution, of which I was one of the founders, commencing at the close of 1799; which Institution has been the principal office for the supplying the world in general, and the Army and Navy in particular, with matter; and where a regular register is kept of each of the cases inoculated. As to Jenner keeping the secret of Cowpox and making a great fortune out of it, Pearson replied, first, that he had not proved his remedy; second, that he would have had to persuade the public to believe in him; and, third, that too much was known about Cowpox to have made a secret possible. Moreover, the assertion that he might have earned £10,000 a year and a fortune of £150,000 was absurd-- Such a fortune no one ever acquired by physic in this or any other country--far exceeding the greatest ever known, those of Sir Theodore Mayerne in the first half of the 17th century, and of the still greater one of Dr. Ratcliffe in the early part of last century.