The two former of these positions need not engage our attention in this place—the highly infectious nature of Small Pox has always been admitted; and I have already brought forward sufficient proof of the danger to human life which it occasions.
The third proposition is of most material importance; for I am well convinced that upon a proper understanding of this question depended the true value of inoculation as far as regarded individuals; and on it also rests the true value of Vaccination as regards society in general.
It was unfortunate for the cause of inoculation that its early advocates maintained the absolute impossibility of Small Pox occurring a second time in the same individual. They thus furnished their opponents with weapons against themselves, in the cases, which repeatedly occurred, of those who had passed through the process of inoculation being afterwards affected by the natural Small Pox; and were put to the necessity of having recourse to expedients equally unmanly and uncandid—either of denying that the second disease was genuine Small Pox, or of asserting that the inoculating process had been imperfectly performed. Whereas a little attentive observation and research into the former history of Small Pox, might have satisfied them, that although in a great majority of cases this formidable disease did not occur a second time in the same person, yet that repeated instances took place wherein it did so occur. And that while it might be assumed as a general rule that the same individual would be affected once only with Small Pox—it was a rule admitting of exceptions.
That a second attack of Small Pox may take place in the same individual, may be proved by a mass of evidence which appears to me to be perfectly irresistible; and as I consider it very important to the object of this enquiry that every doubt should be removed on the subject, I must be permitted to dwell on it longer perhaps than may at first sight appear necessary. I have great pleasure in acknowledging my obligation to the valuable “Historical Sketch of Small Pox,” by Professor Thomson of Edinburgh, for a large share of the evidence which I shall lay before my readers, to prove the frequency of the recurrence of Small Pox. Soon after the introduction of inoculation into France, “a son of M. Delatour, about nine years of age, was inoculated in 1756 for Small Pox, by Surgeon Martin, under the inspection of M. Tronchin, and passed through the disease in a satisfactory manner. This boy remained in good health for upwards of two years, when an eruption, supposed by some to be Small Pox, appeared upon him, as well as upon four of his companions in the same boarding-school. The different opinions formed of the nature of this eruption by the medical practitioners who saw it, and who seem to have judged of it according to the preconceived notions they entertained with regard to the possibility of the recurrence of Small Pox, present (says Dr. Thomson) so true a picture of what has occurred in similar cases since the introduction of Vaccination, and of the manner in which doubtful cases of varioloid eruptions continue still to be judged of, that I cannot avoid giving you an abstract of the discussions to which this case gave rise.”[[6]]—Dr. Thomson goes on to say, that “M. Gaulard, Physician in ordinary to the King, was called to see the son of Delatour on the third day of the eruption, which he declared to be a mild case of Small Pox, of the kind commonly called, he says, though improperly so, Chicken Pox, and the disease in the boy’s companions he considered of the same nature.”—Four physicians were called in to consult with Mons. Gaulard, who[[7]] “gave an account of the progress of the disease which contains a description of varioloid eruptions, very similar to those which have of late been described under the denomination of modified Small Pox.
[6]. Dr. Thomson’s Sketch, &c. p. 53.
[7]. Dr. Thomson’s Sketch, &c., p. 54.
“These gentlemen mention also, that two of the other children affected, had previously passed through natural Small Pox; and conclude with declaring that, from these circumstances, they believe that the disease in Delatour and his companions, was neither the Small Pox nor the Chicken Pox, but a chrystaline eruption, with which they were well acquainted.”
It is, I think, from this sufficiently evident, that nothing but the preconceived opinions of the physicians consulted in these cases could have prevented their acknowledging the true nature of the disease; and there cannot, I conceive, be a doubt, that it was no other than Small Pox rendered milder in its character by the previous occurrence of it in these children. It is of importance too to remember that they afford examples of the recurrence of the disease after both natural and inoculated Small Pox. Delatour had been inoculated upwards of two years before, and “two of the other children affected had previously passed through natural Small Pox.” I shall here adduce some further extracts from Dr. Thomson’s work. He tells us that “M. Hosty, who had been sent over to England in 1755, to acquire information upon the subject of inoculation,” “enters into a discussion with respect to the recurrence of secondary Small Pox, in which he allows that there are several eruptive diseases with which a person may be affected, so like the Small Pox, as scarcely to be distinguishable from them, and, on that account, liable to give rise to many mistakes; and he states, that although he does not deny absolutely the possibility of the recurrence of Small Pox, he believes this to be rare,” (p. 55-6). “To Hosty’s opinion, with regard to the unfrequency of the occurrence of secondary Small Pox, Gaulard replied, that he had at that time under his charge two unequivocal examples of secondary natural Small Pox, and that a nephew of the Archbishop of Paris, had a month before passed through the Small Pox, under the care of the celebrated M. Astruc, although he bore marks on his body of having formerly undergone the disease.”—(p. 59.)