31 8 Progrefs >)/ the Vaccine Imciilatian, anit 



anfwer my query, Whether, in the inftances of the coxv-poS 

 occurring more than once in the fame perfoii, it was certain 

 that the fpecific fever was prefent more than once ? The 

 Dodlor very obUgingly anfwercd my letter, and fays, (fee 

 Dr. Jenner's Letter, p. 99, of my hiquiry,) " You may be 

 affured that a perfon may be repeatedly affeclcd both locally 

 and generally by the cow-pox j two inftances of which I 

 have adduced, and have many more in my recolleftion.'* 

 But he very candidly adds : " Neverthelefs, on this import- 

 ant point I have fomc reafon to fufpect, that my difcrimina-« 

 lions have not been, till lately, fufficicntly nice." 



With refpeft to Faft V. I faid in my Incju'irj, p. 49 : "It 

 ■feems fufficicntly authenticated that people may have the 

 cow-pox after they have had the fniall-pux; but it will re- 

 quire more nice attention to fuisfy the query, Whether, in 

 fuch cafes, the cow-pox afl'ccls the whole conftitution, or is 

 only a local affetStion ? " Subfcquently to this obfervation I 

 find Dr. Jenner himfelf, from a theoretical confideration, 

 ofll-rs as a " conjecture what experiment muft finally deter- 

 mine that they who have had the fmall-pox are not after- 

 wards fufceptible of the primary aclion of the cow-pox virus.'* 

 (Farther Obfervations, &c. by E. Jenner, M.D. &c. p. 32.) 



I fliall now relate the trials I have inftituted, and the oh" 

 fervat'ions I have made, to ohtain iliiermmafiojis whh rcfpc6l~ 

 to thefe important queftions of fa6i:s. 



Trials to determine whetber or not Perjons are fufceptible of 

 having the Cow- POX Pustule and Fever, ivho have 

 undergone the Small-pox. 



The four firft-named gentlemen being engaged with me 

 in profecuting phyfical inquiries, Vvcre defirous to experience, 

 in tixeir o\\w perfons, the eflccls of the vaccine poifon. 



I. Mr. Dangerfield was inoculated in one arm by means 

 of a puncture with a lancet ftained with frefli but dried mat- 

 ter, rendered fluid by fteam juft before it was inferted. The 

 other arm was inocuiated with thread iiiipregnated w ith vac- 

 cine 



