# New Observations on Inoculation/Chapter 2

CHAP. II.
On INSERTION
INSERTION is the application of the variolous matter to some part of the human body. It is well known, that this application takes effect only on some sensible part; therefore, if it is made externally, it must be under the cuticle or scarf-skin, which is an insensible membrane. It is likewise known, that the activity of the virus is so prodigious, that the smallest atom, imperceptible either by sight or feeling, conveys the small-pox equally well with a large quantity.
Hence the most obvious way to perform this operation seems to be, to prick the skin slightly with a pin or needle dipt into a variolous pustule. As nothing is requisite to infuse the poison into the animal system, but to introduce it beyond the scarf-skin, a slight puncture, which divides the membrane, must have appeared sufficient to the earliest operators. The dreadful effects of the poison, which these inoculators had observed in the natural small-pox, could not but make them sparing of it in their first attempts; and tender parents would naturally be equally fearful, and unwilling to put their children to unnecessary pain.
Accordingly we find that, at the first origin of inoculation, in several countries, but especially in those where it was performed by women, the insertion was made in that simple ​manner. The famous Thessalian, who first introduced it in Constantinople, did nothing more; neither did several women who carried it into the islands of the Archipelago, where to this day it is performed in the same manner.
In the dutchy of Urbino in Italy, a grievous epidemical small-pox, that raged in the year 1746, induced several mothers, alarmed at the havock it made, to try to save their children by inoculating them; they had only been told that the thing was practicable; and could think of no other way than to prick the skin with a pin dipt in matter.
Such was the voice both of nature and season; such the practice of the first inoculators; fathers and mothers inoculated in this manner; and so it is that women have always gone about it. Let us now see what art has added, what physicians have done. Soon did they forsake this plain and natural road; soon they devised new and intricate by-paths. Instead of a puncture, an incision was made; the depth was gradually increased; both arms were cut, then the two legs, sometimes all the four limbs. Instruments were contrived for making these incisions; and to a simple operation, which required no care nor apparatus, a variety of inventions were substituted, requiring a long and close attendance, and productive of most evils charged upon inoculation, though merely owing to the way of inoculating.
These several methods, after having deviated from the former simplicity, are gradually ​become less complicate: I shall therefore only examine that which is least faulty, and comes nearest to the original practice. By shewing the inconveniencies which attend it, I shall evince the still greater absurdity of more complicate methods, and the necessity of returning to the primitive operation, as being the most natural, the easiest, safest, and the only one than can be recommended.
Most inoculators actually proceed in the following manner. They make a slight incision or two, only skin-deep; and apply to the wounds either a thread impregnated with matter, or the powder of variolous scabs, secured with a plaister.
This method, simple as it appears, still differs widely from the former, both in itself and in its effects. 1. The first mischief is its being attended with an apparatus and solemnity both needless and hurtful. The business may be done in an instant upon a sleeping child, with little or no pain, if you prick him with a needle, without acquainting him that you are going to give him a distemper. By the other method he must undergo a painful incision, or more than one; a surgeon is employed; sometimes the physician is present; and an operation thus ushered in cannot fail to terrify the child, and set him a-crying. These impressions, though seemingly slight, may greatly affect the success of the whole, as will be shewn hereafter.
2. The infected thread contains an infinite number of those atoms, one of which is ​sufficient to give the small-pox; is it likely that so great a difference in the quantity of this poison, should occasion none in the nature of the future wound? Is it not rather certain, that, cæteris paribus, both the inflammation and suppuration, as well as the number of pustules raised round about the incision, are proportionable to the size of the thread? Every inoculator, as well as myself, must have observed this difference, especially when the insertion is made in two places.
Undoubtedly a greater inflammation, and a more copious eruption about the wound, must add to the greater violence of the disorder. Dr. Lunadei, an Italian physician, is the first who has taken notice, that those whom he inoculated with a pin, were neither so full nor so sick as those, who underwent the common operation. I observed the same thing; and am now far from thinking, as I formerly thought and said, that it is all one whether you put in more or less matter, just as it is whether a mine is set on fire with a spark or a live coal. It is all one as to giving the small-pox, but not so as to the other effects it will have upon the animal system.
3. When the puncture is once made, you have nothing more to do, either before or after the eruption: the little orifice is soon closed, and one or more pustules appear upon the scar, of the same nature and duration with those of the other parts, and requiring no farther care; whereas in the usual method, the eruption about the wound is obstructed, and the humor, which ​should have raised the upper skin and formed into pimples, meeting with an easier passage through the incision, or finding the cuticle softened or wasted by the plaister, necessarily brings on an ulcer. This must be dressed for a fortnight at least; and whilst the principal disorder employs the inoculator but two or three days, the incisions require his attendance for several weeks. Thus a complaint is produced both tedious and painful and not only needless, but also prejudicial to the success of inoculation. It even happens that the ulcer will not heal up, but grows so deep and foul, that the surgeon cannot conquer it in many months and the patient must suffer a thousand times more from this, than from the small-pox itself.
4. It is well known, that sometimes inoculation leaves other bad remains; such as erisypelas', tumors and abscesses, which are very troublesome, and may become fatal. That this is altogether owing to the wounds, will appear if we consider 1, that these complaints never come after the natural small-pox when mild; 2, that they sometimes happen after a confluent pock, when, by opening of the pustules, or by some other accident, ulcers are formed in the leg or elsewhere; 3, that in inoculated persons, these sores, &c. always appear on the side of the insertion, when single; and when made on both arms or legs, then on that where the incision was deepest, and the wound had spread most; and 4, that nothing of this ever happens, when there has been no wound at the place of insertion, but only an eruption. These four ​observations evidently shew, that such accidents arise merely from the incisions, and the treatment of them, and that a skilful practitioner may avoid them if he pleases.
5. By the common method, you are sometimes at a loss to know whether the infection has taken place. The inflammation which appears about the wound, a few days after the operation, is looked upon as a sure proof; but there can be no certainty in this sign, unless you are well assured that it was produced by the variolous matter, and not by any other cause. This you can hardly be, when an incision is made; whereas there can be no doubt from a simple puncture. This presently heals up, and you clearly discern whether the succeeding inflammation is the effect of the needle, or of the infected matter. In the common way, you must take in the effects of the thread and of the putrid matter itself, not merely as conveying the infection, but as extraneous and offensive bodies: and to these are to be added the action of the plaister and of the air. These last causes may produce an inflammation, and about the edges of the cut that white eschar, which inoculators look upon as a decisive sign of the success of their operation. This inflammation often becomes erysipetalous, as in any other wound covered with a greasy plaister; and it may equally bring on pustules, which break out, suppurate, and vanish in one day.
The imperfect likeness of these effects to those of the virus, has sometimes misled inoculators; who, imagining that the venom had ​acted upon the body, and seeing no ensuing small-pox, hastily concluded, that either the subject was not susceptible of infection, or that these appearances were in him equal to the distemper, or the small-pox itself. Hence they pronounced him safe from ever catching it, and neglected to repeat the insertion. But a subsequent natural small-pox shewed that the inoculator was deceived by equivocal signs; and inoculation suffered from his oversight, or rather from the unavoidable uncertainty of the common method.
The enemies of the practice have never failed, upon these occasions, to depreciate it with the public; as most people are ignorant of the difference between being inoculated, and having the small-pox by inoculation; between equivocal signs and a real infection; the accidental suppuration of a wound, and that which necessarily succeeds the variolous fever; and lastly, between pimples that fill and dry off almost in one day, and the true pock, which keeps out nine days at least.
But the cicatrix remaining at the place of insertion, will be a standing monument of the success or failure of it. When the patient has really had the small-pox, this fear is either round, like the mark of a pustule, or oval; but always large enough to be evidently that of an ulcer, and not of a mere incision, as it is when the operation has failed.
By the puncture all errors are avoided. If it brings on ever so slight an inflammation, a few ​days after it was made, it is a sure sign of efficacy; and the succeeding pustules, having all the characteristics of the true small-pox, can leave no doubt of a genuine infection.
Thus have I summed up the chief disadvantages we meet with in practice. They have hitherto been placed to the account of inoculation but l am confident they are solely owing to the manner of performing it. When time, the great restorer of truth, brings us back to the good old method, we shall hear no more of them, and inoculation will be fully vindicated.
I am sensible that many objections will be made against this doctrine. The two principal ones deserving any answer are these:
First Objection."An insertion made by a puncture cannot make way for that copious outlet, which a wound affords to the variolous matter, and which constitutes the greatest benefit of inoculation."
I have in a former work declared my opinion as to the supposed benefit of an outlet, during the course of the distemper. I still think, that this whole doctrine is founded upon superficial notions of the animal œconomy, and a want of due attention to the phenomena of inoculation. Most physicians will, I believe, upon duly weighing my reasons, think, and, what is more, speak as I do.
​For, first, it appears from what has been said, that the discharge at the place of the incision is only occasioned by the matter, which would in that part have produced a cluster of pimples, and not from those of the other parts of the body.
2. Pierce one of the pustules with a needle, so as to let out all the matter, after ten or twelve hours it will be found full again; and by repeating this operation ten or twelve times, the discharge will be proportionally increased, and yet the same quantity remain in all the other pustules.
3. Opening every pustule in order to discharge all the matter, has been frequently attempted, and would certainly be a salutary practice, were the doctrine I oppose founded upon truth. But far from answering the end of thus exhausting the variolous fomes, or preventing the translation of the matter upon nobler parts, new matter was formed as fast as the old was evacuated; the discharge from each pustule was as great as if only one had been opened; the disorder full as dangerous, and much more troublesome; and this process, which in theory appeared excellent, was universally laid aside, as useless, if not pernicious.
4. Lastly, It has never been observed, that a plentiful discharge from the incision was a sign of a slighter disorder. It is, on the contrary, never so considerable as when the discharge is so, and this always keeps pace with the number of ​the pustules. He therefore, who desires a copious outlet, wishes for a considerable degree of danger; and whoever is uneasy at the scantiness of the discharge, shews himself ungrateful to nature, and complains of art, when he has most reason to praise it.
Second Objection. " So slight an insertion does not communicate the small-pox so certainly as the other method."
Several answers may be made to this objection.
1.The inconveniency of missing the small-pox, is of less consequence than the accidents, which may arise from giving it in the common way. When the operation fails, it produces no other effect than the pricking of a pin, and must be repeated.
2.This insertion may be made in several places, without introducing so much of the variolous poison as is conveyed by the usual method or having the same mischiefs to fear. I have inoculated in this manner in five or six places, without the least inconveniency; I only thought the patient had rather a more plentiful crop, and the disorder was somewhat more considerable, than when I made but one puncture. Two or three of these will more effectually communicate the small-pox than the common incisions.
​3. In fact, inoculation is sometimes known to fail, whatever method is used; nor do I think this will happen oftener by this than by any other. We see many patients inoculated with fresh matter, in the usual and strongest manner, yet without any eruption, who afterwards have the small-pox, either in the natural way, or upon a second trial. We likewise daily see people, often and long exposed to the infection, thinking themselves safe, who have afterwards catched the natural disorder. It is certain, there are some who never have it; whole families are free from it for many generations; and it has been observed, that upon a hundred persons dying of old age, five or six had escaped it, though equally exposed with their contemporaries. Inoculators have met with much the same proportion of fruitless attempts. A person in this case can never have an absolute certainty of being for ever safe, but only a probability proportionable to the number of experiments, the goodness of the matter, &c.
It certainly is a desideratum, to be able constantly to communicate the small-pox if the subject is capable of receiving it; or to know, in case of failure, where the fault lies. It is to be hoped this problem will one day be solved, when all disputes about the expediency of inoculation are at an end, and we fix our whole attention on the improvement of it.
In order to attain this desirable end, I would recommend the following rules:
​1. The freshest: matter is the most effectual. Whenever therefore it can be done, the insertion should be made immediately with a needle just dipped in the pus of a pustule. The beginning of suppuration is preferable to a more advanced state, as the matter is then more fluid, and comes off easier from the needle into the wound.
2. Instead of barely pricking the skin, the point ought, if possible, to be introduced between the cuticle and the inner skin, to the length of a quarter of an inch, which is easiest done with a flat-pointed needle. The impregnated needle will keep its virtue for several days, provided it is not rubbed against any thing; but it is always safest to use it soon.
3. Instead of the needle thus dipped, a cotton or silken thread may be used, that has lain some time, and been rubbed with pulverized variolous scabs. This thread may be drawn in with a needle, between the scarf and the true skin, to the length of two or three lines, but not left in. This is the method throughout the Indies.
​4. A lancet may be used instead of a needle; and if only scabs are to be had, the scarf skin should be separated from the true skin, and a little of this powdered matter rubbed against it; the raised cuticle is then to be let down again, and pressed with the finger to make it stick to the skin.
5. Whether a needle or a lancet is employed, care must be taken to apply the matter to the live skin, without going through or tearing it.
6. The variolous virus being thus transferred from the needle, thread, or lancet to the live skin, which lies under the cuticle, this last will sufficiently keep it in, and no plaister is ever to be used.
7. The fittest part for insertion seems to be between the thumb and fore-finger, on the outside of the hand. They do it so in India, Syria, Egypt, and Barbary; and it is preferable on many accompts: the hands are always exposed to the air; the inflammation, which the insertion necessarily brings on, is cæteris paribus smaller and less troublesome, where the skin is least stretched, as in this wrinkled part; the insertion is more easily made there than any where else, because the scarf-skin is thicker, and harder to break; and lastly, the symptoms attending the insertion are more easily observed.
8. These advantages, however, are not so considerable as to make one apprehensive of any great risk from the choice of another place. ​In general, some part of the arm is best; but the legs should never be chosen; for there the pustules are longest a-drying, ulcers are most often formed in the flux small-pox, and continue longest. The Thessalian woman, who inoculated in the forehead and chin, made a better choice than those who inoculate in the legs.
A recent fact, well known and well attested plainly shews the good effects of the method I am contending for.
In some counties in England, where inoculation has for these two or three years been carried on with a success hithrto unknown in Europe, it is performed in the following manner:
The point of a lancet being dipt into a pustule, and moistened with the matter, the person who is to be inoculated is immediately pricked in the arm, so as to introduce the point between the scarf and true skin. The operator then presses down the scarf-skin again with his finger, and all is done. No plaister or fillet is ever used. A few pustules appear afterwards on the part, but never any wound, ulcer, or discharge. Above twenty thousand people have already been inoculated in this manner.
I now come to the method of treatment would recommend; and likewise hope to advance some new truths upon this head.
* ↑ I have long suspected, that the variolous matter became milder by inoculation; and consequently, that a repetition of the like operations would still render it more harmless, though not less efficacious. This conjecture is now to me become a truth, from the experiments I have tried, and those which were made in England by the most experienced inoculators.
* ↑ The authenticity of these numbers must rest upon the credit of the operators.