VACCINATION AGAINST SMALLPOX Ifc 



positive proof, forms presumptive evidence of so forcible 

 a kind that I imagine it might, on any other person, have 

 made the same impression it did on me, without fixing the 

 imputation of credulity. 



First: I conceived this was the source, from observing 

 that where the cow-pox had appeared among the dairies 

 here (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 already 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 Ireland 

 and Scotland, where the men-servants are not employed 

 in the dairies.* 



Fourthly: From having observed that morbid matter gen- 

 crated by the horse frequently communicates, in a casual 

 way, a disease to the human subject so like the cow-pox 

 that, in many cases, it would be difficult to make the dis- 

 tinction between one and the other.* 



Fifthly: From being induced to suppose, from experi- 

 ments, 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 cow-pox of general consti- 

 tutional symptoms which followed.* 



I fear it would be trespassing too far to adduce the gen- 

 eral testimony of our farmers in support of this opinion; 

 yet I beg leave to introduce an extract of a letter on this 



This Information was communicated to me from the first authority. 



The sound skin does not appear to be susceptible of this virus when 

 Inserted Into it, but, when previously diseased from little accidents, its 

 effects are often conspicuous. 



This case (on which I laid no Inconsiderable stress in my late treatise, 

 s presumptive evidence of the fact adduced) seems to have been either 

 mistaken or overlooked by those who have commented upon it. (See Case 

 XV III. p. 36.) The boy, unfortunately, died of a fever at a parish work- 

 house before I had an opportunity of observing what effects would have 

 been produced by the matter of smallpox 



