EIGHTEENTH-CENTURY MEDICINE 



quently developed a virulent form of the disease and 

 died ; or if he recovered, even after a mild attack, he 

 was likely to be " pitted" and disfigured. But, per- 

 haps worst of all, a patient so inoculated became the 

 source of infection to others, and it sometimes hap- 

 pened that disastrous epidemics were thus brought 

 about. The case was a most perplexing one, for the 

 awful scourge of small-pox hung perpetually over the 

 head of every person who had not already suffered and 

 recovered from it. The practice of inoculation was 

 introduced into England by Lady Mary Wortley 

 Montague (1690-1762), who had seen it practised in 

 the East, and who announced her intention of ''in- 

 troducing it into England in spite of the doctors." 



From the fact that certain persons, usually milk- 

 maids, who had suffered from cow-pox seemed to be 

 immuned to small-pox, it would seem a very simple 

 process of deduction to discover that cow-pox inocu- 

 lation was the solution of the problem of preventing 

 the disease. But there was another form of disease 

 which, while closely resembling cow-pox and quite 

 generally confounded with it, did not produce im- 

 munity. The confusion of these two forms of the 

 disease had constantly misled investigations as to the 

 possibility of either of them immunizing against small- 

 pox, and the confusion of these two diseases for a time 

 led Jenner to question the possibility of doing so. 

 After careful investigations, however, he reached the 

 conclusion that there was a difference in the effects of 

 the two diseases, only one of which produced immunity 

 from small-pox. 



" There is a disease to which the horse, from his state 



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