IT is usual to prepare the Patient for this Operation, by Diet and Evacuations, which according to the Habit of Body, are to be more or less severe. Some Physicians recommend frequent Bleedings and Purgings, with a strict Milk Diet, the preceding two Months; others a Regimen of mercurial Alteratives, with gentle Purges at proper Intervals, for the same length of Time; but, I think, those of the greatest Eminence in London seldom prescribe Bleeding more than once, and frequently not at all, trusting to an abstemious Course of Life, and two or three gentle Purges, and sometimes to one only, the Week before the Operation, at least where the Subject is young.

The proper Time for Inoculation is generally supposed to be Infancy; and some think the earlier, the better; but as Children, the first two or three Years of their Life are subject to many terrible Disorders from the Circumstance of breeding their Teeth, and indeed seem more liable to fatal Convulsions upon the Eruption of the Small-Pox, than after that Time, I believe it is adviseable to postpone the Operaration 'till they are three or four Years old, when probably, the longer it is deferred, so much the worse; though the Success of this Practice has been surprising, even in the most advanced Age.

Physicians have not unanimously determined which is the preferable Part for Inoculation, the Arms or Legs; and some order the Operation to be performed in one of each: In either Case, it is right to do it in two Places; though probably it will not be absolutely necessary; but as one of the Applications may by Accident fall off, or slip on one Side from the Orifice, the other will generally take effect, and prevent a Disappointment. The Practice of Inoculating in the Legs is preferred to the other Method by some, from an Observation that the Incisions in these Parts are more disposed to ulcerate and yield a greater Discharge, than those in the Arms, which Circumstance they imagine to be advantageous, upon a Persuasion it makes a powerful Revulsion of the morbid Matter from the Face and Throat: On the contrary, the Advocates for Inoculating in the Arms, advise it for the very Reason, that the Orifices are less liable to become sore and painful; alledging, that the Discharge from the Wounds cannot be favourable to the Eruption, since it seldom happens 'till the Pustules appear, and are even ripe; or should it be judged necessary from the Nature of the Distemper, or the Patient's Constitution, to continue the Discharge, still it may be done as efficaciously in the Arms, by converting one or both Incisions into an Issue. These Considerations have induced the Generality of Physicians to approve of this last Method.

The Operation is to be performed after this manner. You must with a Stocking Needle prick five or six large Pustules on the Arm or Leg of the Subject you inoculate from, when they are plumpest, and the Distemper is at its Height; then taking a few Threads of Lint, roll them up so as to make one Thread, of the Thickness of fine Worsted: draw this over the Orifices made into the Pustules, 'till a sufficient Quantity of it is moistened by the Matter issuing out of them. Cut this Thread into Pieces of the Length of a Barley-Corn, And put them immediately into a little Box or Bottle, which should be shut up close; and, tho' perhaps the Matter may retain its Efficacy for many Hours or Days, yet it is adviseable to use it as soon as possible. It would be of no Importance, what Part of the Arms or Legs were to receive the Infection, but that a Drain may be desireable after the Illness; and therefore the Incisions should be in those Places, where Issues are generally ordered, that by putting in a Pea, you may at pleasure procure a Discharge from them, as long as you shall think proper, a Month, two Months, or more: The Orifices should be cut, with a Lancet, the length of a Barley-corn, and so shallow, as barely to fetch Blood; the Pieces of Lint must be laid exactly on them, and secured in their Situation by a sticking Plaister and Bandage; this Application should remain twenty-four, or thirty-six Hours, and afterwards, the Orifices may be treated every Day with Digestives or other Medicines, according to their Degree of Inflammation, Ulceration and Pain. After the Operation, the Patient must be confined, and live low till the time of the Eruption, which is usually about the eighth or ninth Day, when the Distemper is to be managed as in the ordinary Method.

It is imagined by some, that the Matter from an inoculated Subject, is less malignant than from a Person who has the Distemper, however mildly, in a natural Way; but I think, there is not a sufficient Foundation for this Opinion: It is without doubt proper to take it from a kind sort of a healthy Subject; and though it is not probable any other constitutional Illness will be communicated with the Small-Pox by Inoculation, rather than by the natural Way, which no body even suggests; yet, as we may have choice of Patients to borrow it from, we should not run any risk, but fix on such if possible, who are under nine or ten Years of Age, and whose Parents have always been healthy as well as themselves.

It may not be amiss to observe, that upon the Introduction of the Practice of Inoculation into England, amongst the many popular Prejudices which prevailed against it, there was none of such seeming Weight, as the Opinion that it did not absolutely secure the Patient from contracting the Distemper again in the natural Way; but length of Years, and a strict Enquiry, have at last intirely falsified this Doctrine amongst Men of Learning and Candour. Great Improvements have been made in England since the Publication of the foregoing Chapter, both in the Method of Inoculating, and the Manner of treating the Distemper; but as they are described with great Precision by Baron Dimsdale, I shall refer the Reader to his Pamphlet on this Subject.