348 Bk. MtTKiJAv on Vaccination. 



in early iiifcuicy, (one of which I before mentioned) it was 

 succeeded by regular pocks and constitutional fever ; and in 

 a good many it produced irregular festering vesicles, which 

 were sometimes attended with more or less constitutional 

 irritation. 



From these experiments I was led to think that the result of 

 exposure to variolous contagion in the persons I re-vaccinated, 

 ■would have been analogous lo that which succeeded re-vaccina- 

 tion ; in other words^ that in proportion as their constitutions 

 retained their susceptibility to Vaccine-Pox, they would have 

 heen susceptible oi variolous infection ;* — I had every reason 

 ■however to believe, that the state of perfection of the protective 

 power was not at all altered by the length of interval from the 

 iirst vaccination, but that it depended entirely upon the degree 

 ■of saturation imparted by the first operation, for of those who 

 had been vaccinated for upwards of 20 years, I did not find a 

 larger proportion susceptible of Vaccine action, nor that they 

 were more readily, or more severely affected by it, than those 

 who had been only vaccinated for one year. 



The piesent favorite system in England, to improve the 

 Gecurity of the constitution against Small-Pox, is re-vaccination , 

 founded on the notion of the duration of the vaccine influence 

 in the constitution being limited, and of its ivearing out in the 

 «ourse of a certain number of years ; and I am greatly surprised 

 to find Dr. Gregory still abetting this perturbing notion, seeing 

 that it is clearly proved to be unfounded by much direct 

 evidence both before and since the Jeinierian era of vaccination. 

 I am an advocate for re-vaccination, but upon the principle 

 of its perfecting the assimilation of the disease in the system, 

 as I believe the effect of the primary inoculation to be often 

 imperfect and inefi"ectual, owing to the interference of various 

 causes as above stat-ed ; and on this account I would advise it 

 to be practised in cases where it has been deemed expedient to 

 institute vaccination before the age of three or four months ; or 

 during dentition ; or during the existence of any febrile or 

 cutaneous disorder ; or where the course of the disease has 

 been irregular and imperfect. I would also advise it generally, 

 in event of the occurrence of a variolous epidemic, in any place ; 

 and in persons who are likely to be much exposed to variolous 

 contagion. 



• Mv. Oswald, of tlie Isle of Mnn, mentions, that wlien h varioloid 

 epidemic appeared there, and was found to attack persons who had been 

 previously vaccinated, he prevailed upon some respectable families to 

 submit their children, who had been vaccinated, to variolous inoculation; 

 and the results were similar to those 1 have stated after re-vaccination. 

 In two individuals, variolous disease with scanty eruptions was pro- 

 duced ; in one, the inoculated part became affected, but without any 

 constitutional derangement ; and in the t'thcrs, the virus cfl'cctcd nothina 

 at all. 



