200 EDWARD JENNER 



merely from the primary action of the virus on the con- 

 stitution, .and that those symptoms which, as in the acci- 

 dental cow-pox, affect the patient with severity, are entirely 

 secondary, excited by the irritating processes of inflamma- 

 tion and ulceration ; and it appears to me that this singular 

 virus possesses an irritating quality of a peculiar kind, but 

 as a single cow-pox pustule is all that is necessary to render 

 the variolous virus ineffectual, and as we possess the means 

 of allaying the irritation, should any arise, it becomes of 

 little or no consequence. 



It appears then, as far as an inference can be drawn from 

 the present progress of cow-pox inoculation, that it is an 

 accidental circumstance only which can render this a vio- 

 lent disease, and a circumstance of that nature which, for- 

 tunately, it is in the power of almost every one to avoid. I 

 allude to the communication of the disease from cows. In 

 this case, should the hands of the milker be affected with 

 little accidental sores to any extent, every sore would be- 

 come the nidus of infection and feel the influence of the 

 virus ; and the degree of violence in the constitutional symp- 

 toms would be in proportion to the number and to the state 

 of these local affections. Hence it follows that a person, 

 either by accident or design, might be so filled with these 

 wounds from contact with the virus that the constitution 

 might sink under the pressure. 



Seeing that we possess the means of rendering the action 

 of the sores mild, which, when left to chance, are capable 

 of producing violent effects ; and seeing, too, that these 

 sores bear a resemblance to the smallpox, especially the 

 confluent, should it not encourage the hope that some topi- 

 cal application might be used with advantage to counteract 

 the fatal tendency of that disease, when it appears in this 

 terrific form? At what stage or stages of the disease this 

 may be done with the most promising expectation of suc- 

 cess I will not pretend now to determine. I only throw out 

 this idea as the basis of further reasoning and experiment. 



I have often been foiled in my endeavours to communi- 

 cate the cow-pox by inoculation. An inflammation will 

 sometimes succeed the scratch or puncture, and in a few 

 days disappear without producing any further effect. Some- 







