Before I dismiss the subject, it may not be improper to give some account of the motives that induced me to adopt this method.

During the course of many years practice of inoculating in the former usual method, I generally committed to writing the most remarkable occurrences to have recourse to. Among these, I had recorded some cases, which proved, that those who had suffered most, were in general such as have been kept warm, and nursed with the greatest tenderness and care. These facts disposed me to think of a cooler manner of treating the disease, and made me attentive to the reports of such a method having been practised in some parts of this country with great success, though too extravagant at first to deserve credit.

The reports, however, of this practice still gained ground; and, upon the strictest inquiry, I found they were for the most part true, and that such who were treated in this way, passed through the distemper in a more favourable manner than my own patients, or those of the most able practitioners in the old method of inoculation; also that the inoculators in this new way, enjoined a stricter regimen as to diet, than I had hitherto thought necessary; and that they frequently brought their uninfected patients into the presence of those who had the disease, and inoculated them immediately with fluid matter, taken on the point of a lancet, and by a very slight puncture or incision; applying no dressing or covering afterwards.

This way of performing the operation pleased me, as far as related to the slightness of the incision, and the use of fresh matter; for I had (in common with other inoculators) sometimes failed of infecting, by using a thread that had been kept too long in a phial: but the circumstance of bringing the person to be inoculated into the presence of one who had the small-pox, seemed hazardous, lest there might be an accumulation of infection.

All doubts, however, were at last removed by the authenticated accounts that I received of these particulars, and of the good success that attended the practice; and I began to try it in January 1765; when, after having directed a strict regimen and some mercurial purges, I inoculated with fluid matter, proceeding with much circumspection and attention; my patients being exposed to the open air in that cold season. The great advantage they received from this treatment was soon apparent, and more than sufficient to encourage my continuance in the practice; till repeated experiments induced me to think, that instead of supposing the fever in the small-pox to be the instrument employed by nature to subdue and expel the variolous poison, we should rather consider it as her greatest enemy, which, if not vigorously restrained, is apt to produce much danger; and that all such means should be used as are most likely to control its violence, and extinguish the too great fervor of the blood. Pursuant to this opinion, besides keeping my patients in the open air, which I had learned from others, I first directed the mercurial and antimonial medicine, and the laxative course in the eruptive state; the manner of administering which, and the success attending, has been already related.

It may perhaps appear singular that bleeding has neither been once mentioned or directed in the course of this work, though by general consent it is allowed to be the most efficacious remedy in all inflammatory cases. To this I can only say, that the regimen and medicine above prescribed commonly reduce the patients so much as to render bleeding unnecessary. And in the natural small-pox it seemed most reasonable to adhere, as strictly as possible, to those measures which had contributed apparently so much towards passing so easily through inoculation. I doubt not, however, that cases will arise, in which bleeding may not only be safe, but extremely salutary.

It will, I hope, be needless to tell the reader, that I have disclosed the whole of what I know with certainty relative to this process, as the regimen, medicines, different types of the disease, the rules of prognostic, and various events, &c. are fully and faithfully related, according to the best of my judgment and experience. And I believe, if the method now recommended is carefully pursued, it will be found to answer with a success at least equal to any yet discovered. Nevertheless it is reasonable to suppose, that further experience may produce some improvements: yet when it is considered, how short a time is required for preparation; how few medicines are to be taken; that those medicines are neither nauseous in themselves, nor violent in their operation, and of a kind likely to be beneficial to most constitutions, and hurtful to none, unless injudiciously administered; that the disease is usually so mild, as to require little or no confinement (the complaints of far the greater number being that they have too little of the distemper); and that the disagreeable consequences which sometimes happened after the former method of inoculation are likewise by this most commonly obviated; I do not see that much alteration can be even wished for. That which appears most likely to be made, is in shortening the time of preparation; for as I have often been obliged to inoculate without any, and have always had the same success, it has inclined me to think, that much, if not the whole, of this process, may be dispensed with, except in very full habits, or where other particular circumstances may require it. But in all these cases, from the insertion of the matter to the time of the eruptive complaints, the patients have been kept to a close observance of diet, and the use of the preparatory medicines, proportioned as well as I could to their condition: for I durst not, by way of experiment, dispense with the use of measures that had been hitherto so successful.

Should it be asked then, To what particular circumstance the success is owing? I can only answer, that although the whole process may have some share in it, in my opinion it consists chiefly in the method of inoculating with recent fluid matter, and in the management of the patients at the time of eruption. If these conjectures should be true, perhaps we should be found to have improved but little upon the judicious Sydenham’s cool method of treating the disease, and the old Greek woman’s method of inoculating with fluid matter carried warm in her servant’s bosom.