290 



On Vaccination. 



appeared liad been vaccinated when the cow-pox v/as first 

 introduced into France ; and as no details are given, it is very 

 possible that the disease communicated was the false cow-pox, at 

 that time so common in this country. All the other childreny 

 vaccinated in the same place, and at later periods, continued 

 exempt from tlie small-pox. There is a fact, which was verified 

 by several members of tiie committee, and we ourselves saw the 

 infant covered w ith a very numerous, but favourable small-pox, 

 on the 7tti December, 1806'. This child, called Emma 

 Kerouenne, lived in the old street of the Temple, No. 93, and 

 had been successfully vaccinated on the 24th March, 1804, by 

 M. Lanne, pliysician in Rue Fran^ais, who had preserved aa 

 account of the vaccination, and its progress. It is therefore 

 evident that it is not impossible for a child that has been vacci- 

 nated to be afflicted with the small-pox. Nor indeed ought we 

 to look for any such impossibility, as it has been well ascertained 

 not to hold, even after inoculaiion, with the matter of small- 

 pox. 



But what degrees of probability do these observations leave, 

 that vaccination will be a preservative from small-pox ? We 

 iDay obtain it by comparing the nimiber of individuals who have 

 taken the smaU-pox after vaceiuation with the whole number 

 vaccinated, and who have not caught the infection, though 

 repeatedly exposed to it. Another base of this evaluation is the 

 number of counter experiments made, either by inoculation, or 

 by placing persons that htive been vaccinated in contact with 

 those that are afflicted with the small-pox, « 



If we take the result of the correspondence of the central 

 committee of Paris, the seven observations above-mentioned, 

 supposing them all exact, are to be opposed to no fewer than 

 2,671,652 cases of vaccination. Jf it be objected that these 

 seven observations, the only ones with which the committee 

 were acquainted, are in all probability not the only ones which 

 have occurred in the empire, we answer, that even these seven 

 are not altogether free from uncertainty; and that the 2,67lj(>6'i 

 vaccinations mentioned by the committee are far from being the 

 whole number hitherto performed in France. These two num- 

 bers, being the whole obtained by the same means, are very 

 fairly comparable with each other. They give us the ratio of 1 

 to 381,666. 



With respect to counter-experiments, they are of three kinds : 

 those made by inoculating with small-pox virus ; those resulting 

 from coming in contact with infected persons; those resulting 

 from the reports of epidemic small-pox in villages, from which 

 very few persons escape. The accounts transmitted to the 

 committee present 640 individuals put to the test of inoculation ; 

 680 persons living with individuals afflicted with the small- 



