172 EDWARD JENNER 



it renders the constitution unsusceptible of the variolous, 

 should nevertheless, leave it unchanged with respect 

 to its own action. I have already produced an instance 14 

 to point out this, and shall now corroborate it with 

 another. 



Elizabeth Wynne, who had the cow-pox in the year 1759, 

 was inoculated with variolous matter, without effect, in the 

 year 1797, and again caught the cow-pox in the year 1798. 

 When I saw her, which was on the eighth day after she re- 

 ceived the infection, I found her affected with general lassi- 

 tude, shiverings, alternating with heat, coldness of the ex- 

 tremities, and a quick and irregular pulse. These symptoms 

 were preceded by a pain in the axilla. On her hand was 

 one large pustulous sore, which resembled that delineated in 

 Plate No. i. (Plate appears in original.) 



It is curious also to observe that the virus, which with 

 respect to its effects is undetermined and uncertain previously 

 to its passing from the horse through the medium of the 

 cow, should then not only become more active, but should 

 invariably and completely possess those specific properties 

 which induce in the human constitution symptoms similar to 

 those of the variolous fever, and effect in it that peculiar 

 change which for ever renders it unsusceptible of the vario- 

 lous contagion. 



May it not then be reasonably conjectured that the source 

 of the smallpox is morbid matter of a peculiar kind, gener- 

 ated by a disease in the horse, and that accidental circum- 

 stances may have again and again arisen, still working new 

 changes upon it until it has acquired the contagious and 

 malignant form under which we now commonly see it making 

 its devastations amongst us? And, from a consideration of 

 the change which the infectious matter undergoes from pro- 

 ducing a disease on the cow, may we not conceive that many 

 contagious diseases, now prevalent among us, may owe their 

 present appearance not to a simple, but to a compound, ori- 

 gin? For example, is it difficult to imagine that the measles, 

 the scarlet fever, and the ulcerous sore throat with a spotted 

 skin have all sprung from the same source, assuming some 

 variety in their forms according to the nature of their new 



" See Case IX. 



