Experiments feJ]'eBmg the Vaccine Difeafc. ^7,^ 



1 fubmit ' to Dr. Woodville, whether or not that evidence 

 is admiflible to build upon, now tnat we have the above un- 

 equivocal contra\'ening cafes of the fa6t aflerted. But I truft 

 the Doftor will be lefs tenacious of this inflance, as he him- 

 felf tells us that he failed to excite the vaccine difeafe by 

 inoculating feveral patients who were recovering from the 

 natural fmall-pox. {Reports, p. 1^4.) 



Whatever impreffion the above inftances may have mad* 

 on niy own niiud, I do think they will produce convidion in 

 the mind of every practitioner, that it is a law of the human 

 animal (economy to be rendered unfufceptihle of the covj-pox 

 fever and fecific pufule hy undergoing the fmall-pox. Hence 

 I find that my expeflation of the hands of phyfic being 

 ftrengthened by the pnfleffion of a fure means of exciting an 

 innocent fever is not realifcd, {Inquiry, p. 8];) but I feel 

 fome confolaliou from the profpeil: of the new incculatioii 

 being more fpcediiy introduced by the removal of one ob- 

 ftacle, viz. the fears of many pcrfons, who have already 

 palfed through the fmall-pox, that they would be liable to 

 the covv-poXj if the difFufion of the infection of it became 

 extenfive by the vacci\ie inoculation. Another advantage 

 fuggefted in my Inqidry, p. 92, is now, I think, greatly con- 

 firmed ; namely, an advantage for ihofe luho are nt/t certain 

 luhclher or not thiy have had the fmall-pox, hut foffifs fo 

 great a dread of this difeafe as not to he able to fubmit to 

 inoculation for it. I congratulate fuch perfons on the dif- 

 covery of a teft to which I apprehend the more timorous 

 minds will fubmit : for if the fpecific pufule and fever do 

 not take place from the inoculation of the cow-pox poifon, 

 they may be airured, that either they have already pafl(?d 

 through the fmall-pox, or that their conftitution^ arc not 

 fufceptible of it. 



It now feems to me, that the following facts are eftabUflied 

 on the ground of experience : — 



I. A conjlitntion which has undergone the fmall-pox, is 

 unjufceptible of again undergoing this difeafe, 



Y a II. A 



