VACCINATION. 



lion, wliich, at the fame [time tliat it is more mild in its 

 fymptoms than that produced by accidental infection, does 

 neverthelefs ftill operate fuch a change in the conftitution, 

 as renders the perfon inf :>S''d unfufceptible of the fmall- 

 pox.. 



The want of vaccine mati^er now prevented Dr. Jenner 

 from proferuting his experiments until the fpring of the 

 year 1798, when the cow-pox again became prevalent 

 among the cows in the dairies in his neighbourhood, and 

 afforded him an opportunity of inveiligating farther this 

 interefting fubjeft. 



With matter taken from cow-pox veficles on the teats of 

 a cow. Dr. Jenner now inoculated feveral perfons ; and 

 from thefe perfons he propagated the affeftion to others, 

 alfo by inoculation, even fo far as the fifth change, without 

 recurring to the original fource, the veficles on the teats 

 of the cow. The experiments were completely fuccefs- 

 ful. The afTeftion, in all thofe inoculated, was regularly 

 [produced. All the perfons who had been thus infedled, 

 iwere afterwards fubjedled to inoculation with the virus of 

 the fmall-pox, but ineffedlually, no dlfeafe in any inftance 

 fucceeding to this operation. See Jenner's Inquiry, p. 43. 

 1 From thefe experiments, we derive another mod im- 

 portant faft concerning the nature of cow-pox, viz. that 

 the virus of cow-pox may be propagated from one human 

 Ifubjeft to another, through feveral gradations, and ftill 

 retains the power, not only of producing the affeftion, 

 regular in all its ftages, but alfo of rendering thofe con- 

 iftitutions which are infefted, fecure againft the attacks of 

 fmall-pox. 



; By unwearied attention to all the circumilances under 

 Lvhich he was accuftomed to obferve this ailment, Dr. Jenner 

 K3S led to conclude, that perfons who have already had 

 -.he fmall-pox, are ftill fufceptible of the aftion of cow-pox, 

 1 hough not to fuch a degree as thofe who have never been 

 ;ijbi :fted to that of fmall-pox. 



I 'i'hat in the cow-pox no eruption takes place, unlefs on 

 lie part where the virus is applied to the fliin. 

 ) That the cow-pox, even under the moft unfavourable cir- 

 ;umftances, has never proved fatal. 



I That the cow-pox cannot be propagated by contagion, 

 jmt only by aftual contaft, or inoculation with the virus. 



Tiiat the virus of the cow-pox, inferted into the human 

 ,iody, may produce an affeftion which is merely local, the 

 |;eneral conftitution remaining unaltered ; and that, in fuch 

 |afes, the perfon is ftill hable to be infcfted with the 

 imall-pox. 



I Soon after Dr. Jenner's publication appeared, i-Vz. in 

 iCovember, 1798, Dr. George Pearfon publiftied " An 



nquiry into the Hiftory of Cow-pox, principally with a 

 l^iew to fuperfede and extinguifti the Small-pox." In this 

 Ireatife, the pofitions and conclufions of Dr. Jenner are 

 xamined with that candour and attention, which their im- 

 jortance demand. The evidences adduced are numerous 

 jnd refpeftable, and the refult is highly favourable to the 

 leneral introduction of inoculation for the cow-pox among 

 liankind, not only as a preventive of fmall-pox, but alfo 

 i3 a certain mode of ultimately extinguifiiing that loathfome 

 .lalady. 



I In May, 1799, were publiflied " Reports concerning a 

 |eries of Inoculations for Cow-pox, with Remarks and 

 j)bfervations on this Difeafe, confidered as a Subftitute for 



mall-pox, by Dr. Woodville, Phyfician to the Small-pox 

 I id Inoculation Hofpital in London." The account here 

 liven by Dr. Woodville is very different from that given by 

 ])r. Jenner, and by no means favourable to the general in- 

 loduftion of the new inoculation as a fubftitute for fmall- 



I 

 I 



pox. Such a report, coming from a man of Dr. Wood- 

 ville's known charafter and reputation as an accurate ob- 

 ferver, naturally produced a ftrong fenfation in the minds of 

 medical men concerning the diicoveries of Dr. Jenner. 

 Tlie circumftances, however, under which Dr. Woodville's 

 obfervations were made, and upon which his reports were 

 founded, were fuch as led him to be much deceived refpeft- 

 ingthe true nature of the cow-pox. 



This report of Dr. Woodville, fo very different from the 

 general itatement of Dr. Jenner, naturally called for a reply 

 from the latter, who accordingly, in 1800, publifhed " A 

 Continuation of Fafts and Obfervations relative to the 

 Variola; Vaccinas." In this publication, Dr. Jenner is 

 anxious to recover his favourite fubjeft from that degree of 

 fhade, which had been thrown upon it by the hafty reports 

 of Dr. Woodville ; and this he appears to have done with 

 great fuccefs, both by farther obfervations of his own, and 

 by the concurring evidence of many refpedlable correfpond- 

 ents. See Bryce's Praclical Obfervations on the Inoculation 

 of Cow-pox, chap. I. edit. 2. 



With regard to Dr. Woodville's publication, we (hall 

 merely add in the prefent place, that the cafes reported by 

 him as examples of inoculated cow-pox, attended with many 

 fevere fymptoms, and particularly with an eruption over the 

 body, have been fully proved, and indeed have been fince 

 allowed by that refpettable phyfician himfelf, to have been 

 in faft cafes of genuine fmall-pox, the infedlion having been 

 contrafted in the place where tlie patients were inoculated 

 with cow-pox virus, before this latter aft'eftion had pro- 

 duced the effefts and changes in the conftitution, which 

 render it a preventive of the other loathfome malady. 



For additional particulars relative to the tirft progrefs of 

 vaccination, we muft refer to the article Cow-Pox : fuffice 

 it here to fay, that every objeftion to the praftice was 

 gradually removed ; the public became convinced of its 

 value and beneficial confequences ; the great founder of it 

 received an honourable remuneration from his country ; both 

 neighbouring and remote nations foon took a deep intereft 

 in the fubjett, and imitated our example; public inftitutions 

 for the gratuitous inoculation of the poor were in a fhort 

 time eftabliflied in every civilized country ; and the great 

 benefits of the new plan were quickly extended to all the 

 four quarters of the globe. 



Defcription of the regular vaccine Veftcle. — When vaccina- 

 tion fueceeds, a fmall red fpot is obfervable on the third 

 day, the day upon which the operation is performed being 

 reckoned the firft. If the fpot be touched, an elevation is 

 felt ; and if examined with a magnifying glafs, the little 

 tumour appears to be furrounded by a very flight efflo- 

 refcence. 



The fpot gradually enlarges ; and between the third and 

 fixth day, a circular vefiele appears. The edge of the 

 vaccine veCcle is elevated ; the centre depreffed. The co- 

 lour is at firft of a light pink, fometimes of a blueifti tint, 

 and changes by degrees to a pearl colour. The centre is 

 fomewhat darker than the other parts. 



The veficle is hard to the touch. 



In its internal ftrueture it is cellular, the cells being filled 

 with tranfparent lymph. 



The velicle commonly augments, till the tenth or eleventh 

 day. 



In the early ftages, there is ufually round the bafe an 

 inflamed ring ; or this takes place on the feventh or eighth 

 day. About the ninth, it fpreads rapidly ; and near the 

 tenth, it forms an areola of an inch and a half in diameter. 

 This areola is of tiie ufual colour of inflamed fkin ; it is hard, 

 and accompanied with feme degree of tumefaftion. 



It 



