670 SUPPLEMENTARY APPENDIX. 



cases of natural small-pox of which the inoculated cases were in one way 

 or other the cause, it seems probable that inoculation did tend to increase 

 the prevalence of small-pox ; but there are no recorded data to show that 

 this really was the case, and this supposed influence may have been 

 counterbalanced by other influences. 



The evidence as to the influence which inoculation had on the 

 mortality from small-pox is in many respects conflicting. Haygarth, 

 though he admits that in other parts of the kingdom the practice may 

 have saved many lives, was persuaded that in his own part of England 

 and Wales the deaths by the small-pox had been augmented by it ; and 

 he points out that in London, Geneva, and other " towns in different 

 situations and circumstances, the mortality from this distemper has 

 increased since the introduction of inoculation." Several writers in the 

 latter part of the last, and the early part of the present century, held 

 a similar view. Other writers, again, opposed this view. 



Tradition of the Dairy-folk. 



There was at the close of the eighteenth century, if not earlier, in 

 districts where cow-pox had appeared, a belief among the dairy-folk that 

 those who had taken the cow-pox never took the small-pox ; and indeed 

 one Jesty, a Dorsetshire farmer, had in 1774, in the case of his wife and 

 sons, purposely introduced the matter of cow-pox into the human subject 

 with the view of protecting from small-pox. 



Cow-pox. 



Vaccinia or cow-pox is a disease affecting milch cows, and marked by 

 an eruption on the udder and teats. The disease can be communicated 

 from the cow to man. Dairymen and maids engaged in milking cows 

 affected with cow-pox are apt to have sores of a special kind on their hands 

 or elsewhere, the development of the sores being frequently accompanied 

 by febrile symptoms. There can be no doubt that, in a certain number 

 of cases at all events, such sores are the local manifestations of cow-pox : 

 the virus from the eruption on the cow being introduced into some scratch 

 or other imperfection in the skin of the milker and there producing its 

 local effects, accompanied more or less by general symptoms. 



Inoculation of Cow-pox. 



The practice, however, of inoculating with the matter of cow-pox, or 

 vaccination as it was subsequently called, may be considered as dating 

 from the publication of the " Inquiry into the Causes and Effects of the 

 Variolae Vaccine " of Edward Jenner, published in the summer of the 

 year 1798. The practice rapidly spread, and prevailed widely in this 

 country and other parts of western Europe during the first quarter of the 

 present century. It was, beyond all question, so adopted in the genuine 

 belief that it afforded protection against small-pox. 



In the treatise to which reference has been made Jenner records in the 

 first place a number (19) of cases in which a person who had accidentally 

 taken cow-pox from the cow had never had small-pox, and appeared 



