The patient to be infected being in the same house, and, if no objection is made to it, in the same room, with one who has the disease, a little of the variolous matter is taken from the place of insertion, if the subject is under inoculation; or a pustule, if in the natural way, on the point of a lancet, so that both sides of the point are moistened.
With this lancet an incision is made in that part of the arm where issues are usually placed, deep enough to pass through the scarf skin, and just to touch the skin itself, and in length as short as possible, not more than one eighth of an inch.
The little wound being then stretched open between the finger and thumb of the operator, the incision is moistened with the matter, by gently touching it with the flat side of the infested lancet. This operation is generally performed in both arms, and sometimes in two places in one arm, a little distance from each other. For as I have not observed any inconvenience from two or three incisions, I seldom trust to one; that neither I nor my patient may be under any doubt about the success of the operation from its being performed in one place only.
I have also tried the following method, with the same success as that above described, but do not so well approve of it, because I have been credibly informed that it has sometimes failed in the practice of others. A lancet being moistened with the variolous fluid in the same manner as in the other, is gently introduced, in an oblique manner, between the scarf and true skin, and the finger of the operator is applied on the point, in order to wipe off the infection from the lancet, when it is withdrawn. In this method, as well as in the former, a little blood will sometimes appear, but I neither draw blood with design, nor do I think it necessary to wipe it off before the matter is introduced.
In both these ways of inoculating, neither plaister, bandage, or covering is applied, or in any respect necessary.
These methods of producing the disease never once have failed me; and experience has sufficiently proved, that there is no danger from additional infection by the natural disease at the same time. I therefore make no scruple of having the person to be inoculated, and the patient from whom the infection is to be taken, in the same room; nor have ever perceived any ill consequences attending it. But I advise the inoculated patients (though perhaps there is no necessity for that precaution) to be afterwards separated from places of infection till certain signs of success appear, when all restraint is removed, there being no danger from accumulation.
It seems to be of no consequence whether the infecting matter be taken from the natural or inoculated small-pox; I have used both, and never have been able to discover the least difference, either in point of certainty of infection, the progress, or the event: and therefore I take the infection from either, as opportunity offers, or at the option of my patients or their friends.
Nor is it of consequence whether the matter be taken before, or at the crisis of, the distemper. It is, I believe, generally supposed, that the small-pox is not infectious till after the matter has acquired a certain degree of maturity; and in the common method of inoculation, this is much attended to; and when the operation has failed, it has commonly been ascribed to the unripeness of the matter.
But it appears very clearly from the present practice of inoculation, that so soon as any moisture can be taken from the infected part of an inoculated patient, previous to the appearance of any pustules, and even previous to the eruptive fever, this moisture is capable of communicating the small-pox with the utmost certainty. I have taken a little clear fluid from the elevated pellicle on the incised part, even so early as the fourth day after the operation, and have at other times used matter fully digested at the crisis, with equal success. I chuse, however, in general, to take matter for infection during the fever of eruption, as I suppose it at that time to have its utmost activity.
In all cases, when I take matter from an inoculated person, it is from the place where it was inserted; as I am always sure to find infection there if the disease succeeds, and always of sufficient energy.
It may appear strange that no bandage, dressing, or application whatsoever, is made use of to the part infected; but that the most simple incision being made, and moistened with the smallest particle of the recent fluid matter, the whole is committed to nature. This method is however perfectly right, because the application of either plaister or unguent, as is the usual practice, will occasion an inflammation on some skins, and in all tend to disguise the natural appearance of the incision, and prevent our forming a proper judgment of the progress of the infection; which will afterwards appear to be a matter of much importance.
If neither an inoculated patient is at hand, nor any one in the neighbourhood has a distinct kind of the natural disease, a thread may be used as in the common manner, provided the thread be very recently infected; but I think it ought to be used as soon as possible after being charged with infecting matter.
The following method of introducing the disease has likewise been found effectual; but I have never practised it myself. Dip the point of a lancet in variolous matter; let it be held in the air till it is dry; after which it may be closed and kept in the common case without any further care; and with this prepared lancet raise the scarf skin obliquely, and keep the lancet a little time in motion between the two skins, that part of the matter may be mixed with the animal juices; then withdraw the lancet, and leave the incision uncovered as before.
Of the Progress of Infection
Hitherto very little regard seems to have been paid to the progress of infection discoverable by the part where the operation was performed. But it will appear in the sequel, that an attention to this circumstance is very necessary, because a just prognostic may thence be sometimes formed of the future state of the distemper, and indications may be taken from the different appearances on the arm, that will enable us to prevent inconveniencies.
The former method of covering the place of incision with a plaister, and continuing upon it dressings of one sort or another, prevented much useful information of this kind. They prevented any judgment by the touch, and sometimes rendered that by the eye equivocal.
The day after the operation is performed, though it takes effect, little alteration is discoverable. On the second day, if the part is viewed with a lens, there generally appears a kind of orange-coloured stain about the incision, and the surrounding skin seems to contract. At this time I usually give the following medicine at going to bed, either mixed with a little of any kind of jelly, or more frequently made into a pill.
Calomel and compound powder of crabs claws, of each 3 grains, emetic tartar 1⁄10 of a grain.
A quantity of this medicine should be carefully prepared at once, in order to make the division more exact.
On the fourth or fifth day, upon applying the finger, a hardness is to be felt by the touch. The patient perceives an itching on the part, which appears slightly inflamed; and under a kind of vesication is seen a little clear fluid; the part resembling a superficial burn. About the sixth, most commonly, some pain and stiffness is felt in the axilla; and this is a very pleasing symptom, as it not only foretells the near approach of the eruptive symptoms, but is a sign of a favourable progress of the disease. Sometimes on the seventh, oftener on the eighth day, symptoms of the eruptive fever appear; such as slight remitting pains in the head and back, succeeded by transient shiverings and alternate heats, which in a greater or less degree, continue till the eruption is perfected. At this time also it is usual for the patient to complain of a very disagreeable taste in his mouth, the breath is always fetid, and the smell of it different from what I have ever observed in any case, except in the variolous eruptive fever.
The inflammation in the arms at this time spreads fast; and upon viewing it with a good glass, the incision, for the most part, appears surrounded with an infinite number of small confluent pustules, which increase in size and extent as the disease advances. On the tenth or eleventh day, a circular or oval efflorescence is usually discovered, surrounding the incision, and extending sometimes near half round the arm, but more frequently to about the size of a shilling; and being under the cuticle, is smooth to the touch, and not painful. This appearance is also a very pleasing one; it accompanies eruption; every disagreeable symptom ceases; and at the same time it certainly indicates the whole