infected cows and begot pox was a blunder, which he explicitly reversed fifteen years afterwards in his letter to Moore of 27th October, 1813, already cited-- I am sorry [he wrote] you have not succeeded in infecting a cow. I have told you before that the matter which flows from the fissures in the horse’s heel will do nothing. It is contained in vesicles and the surrounding skin.[157] Jenner, we have always to remember, was a slovenly investigator, not apt to take pains, but apt to eke out observation with invention. His friend, “honest Jack Baron of Gloucester,” who himself inoculated with horse virus unmodified by the cow, actually wrote Jenner’s life in two volumes, and not until the work was ready for the binder did he discover that he was in error in common with his master in ascribing Cowpox to Horsegrease! Such was the intellectual muddle in which these prophets of vaccination operated! In a note stuck at the end of the second volume, we have the following amazing confession, made, remember, in 1838, fifteen years after the chief conjurer’s death-- I take this opportunity of expressing my regret that I have employed the word _Grease_ in alluding to the disease in the horse. _Variolæ Equinæ_ is the proper designation. It has no necessary connection with the _Grease_, though the disorders frequently co-exist. This circumstance at first misled Dr. Jenner, and it has caused much misapprehension and confusion.[158] Here we have the secret and desired explanation. It was out of Horsepox, and not out of Horsegrease, that Cowpox was derived, and in confounding grease with pox, Jenner mystified himself and others, and obscured the whole doctrine of vaccination. The Macedonian farriers who in 1803 informed La Font that they recognised three sorts of grease, and one of them variolous, were more accurate observers than the Gloucestershire farriers and farmers whose opinion Jenner lazily retailed. Whether he had any clear apprehension of his own blunder is not apparent. We have seen how long it took his biographer, Baron, to find it out. This is certain, that he made no public attempt to set right what he had so egregiously set wrong, nor to withdraw the statement in his _Inquiry_ that Horsegrease only acquired its efficacy against Smallpox after inoculation on the cow. Lastly, we may inquire what is the present state of opinion as to Horsegrease and Cowpox? When difficult questions are asked, we usually turn to our cyclopædias, and taking down Hooper’s _Lexicon Medicum_, 8th ed. 1848, Art. Cowpox, we read-- It is now ascertained that the horse and the cow each furnish, independently of the other, a virus capable of communicating genuine Cowpox to the human subject. Genuine Cowpox communicated by a horse is surely a bull of the first magnitude! The _Encyclopædia Britannica_, 8th ed. 1860, Art. Vaccination, illuminates us thus--