the Practice of Vaccination. . 295 



previous vaccine disease of its usual malignity*." Dr. Willan 

 stales, that the f'everishness which precedes the eruption in 

 these cases is often considerable, but the pustules are small 

 and hard, containing little or no matter, and begin to dry 

 off on the >ixth dayf. It must not be oniitted, indeed, 

 that in a very few instances the small-pox subsequent to 

 vaccination has assumed the confluent form, and put on a 

 dangerous aspect (as in the recent case of the son of earl 

 Grogvcnor); but even in ihese rare instances, the modifying 

 influence of the previous vaccination has been manifest, the 

 disease, when near its height, receiving a sudden check, and 

 the recovery being unusually rapid |. One case of this sort 

 occurred to the observation of the writer of this paper, iii 

 which, on the seventh day of confluent small-pox, the 

 child became suddenly free from constitutional complaint, 

 and ran aljout at pl:iy ; a circumstance, he believes, that is 

 never known to occur in confluent small-pox where the 

 previous influence of vaccination had not been exerted. In 

 this statement, then, we have admitted the worst conse- 

 quences that have ever accompanied the "failures" of vac- 

 cination, in any one instance. 



But, in the second place, let us attend to the proportion- 

 ate number of these failures. " It does not appear," says 

 Dr. Wdlan, who minuted the cases as they happened, "• that 

 failures in the preventive eflect of vaccine inoculation, in- 

 cluding mistakes, 7iegUgences, and mis-statements, have oc- 

 curred in a greater proportion than as one to eight hun- 

 dred^.' It is very improbable, then, that the actual failures 

 amount to one in a thousand, or to any thing near that 

 nundjer. But let us suppose, for the sake of argument, 

 that the failures amount to the proportion of one in five 

 hundred ; that is to sav, that one of every five hundred per- 

 sons vaccinated remains liable to be infected by small-pox; 

 and let us further imagine, that this subsequent small-pox 

 is not niitigated in any case, and therefore, that (as in the 

 case of the ordinary natural small-pox) one in six of these 

 will die. Then the worst result would be, that one out of 

 every three thousand persons vaccinated would die. But 

 we know, thai one o\ three hundred persons, who receive 

 the small-pox by inoculation, perishes of that disease j|. The 

 conclusion is therefore obvious, that the worst result that 

 could be calculated upon from vaccine failures, would leave 



• See the Report of the Collcfje. + See his Treatise, sect. iv. 



I Seethe last Report of the National Vaccine Hsiahlisiimcnt, July, 1817. 

 5 Sec his Treatise, p. 2:5. || Dr. Willan slates, th.it "the inoculated 



snull-pox still proves fatal in oue ca=e out of livo ktuidrcd andjijhj. — Ibid. 



1^ 4 the 



