collected by thofe who have inquired into the affair, it is plain, that fcarce one in a hundred dies by the inoculated fmall-pox; whereas many more in proportion are deftroyed by the ordinary disease.

A remarkable inftance of this difference, and with what fecurity this tranfplanting the distemper may be made, is given in the following relation, communicated to me by a gentleman of great credit. He was a merchant at St Christopher's, in the West Indies, and in the making of fugar (which is the trade of that place) employed a great number of flaves. In one year, when the fmall-pox raged with more than ordinary violence in the neighbouring iflands, with his own hands, he inoculated three hundred of them, from five to thirty years of age, with such success, that not one of them died, though most of them were negroes. And whereas all the Americans fuffer this diftemper in a moft terrible manner; yet experience fhews, that it is much more dangerous, when it attacks the natives of Africa.

Things being thus, it may be proper to confider, whether any reafons can be alleged to the contrary. And, in the firft place, there are fome who infift upon it, that the eruptions produced by inoculation are not the genuine fmall-pox, and confequently that they cannot fecure any one from having the disease hereafter. Moreover, they take pains to bring testimonies of patients, who, after having undergone the artificial distemper, have nevertheless been afterwards feized with the true one.

Now, I own, I cannot understand how contagion, that is, the very feed of the difeafe, fhould produce, not its own proper diftemper, but another of a quite

different

different kind.

Neither certainly does it matter, by which way the infection is received, provided it brings forth manifeft marks of the disease. And as to those, who, after having been inoculated with fuccefs, are, notwithstanding this, faid to have fuffered the fmallpox; I must protest, that, after the most diligent inquiry, I have not been able to find out one convincing proof of this kind. I very well know, that a story is fpread abroad, particularly by a late author, of a boy, upon whom, about three years after he had contracted the difeafe by inoculation, it broke out again. But I am well affured, that this narration is of doubtful credit; and that there were fome of the family, who affirmed, that no finall-pox appeared upon the inoculation; that the parents (as we easily believe what we with) deceived themfelves, and that the by-standers did not care to take away from them this pleasing mistake.

But to speak plainly, if fuch a thing happened once, why do we not fee it come to pafs oftener ? Or what can a fingle example, fuppofing it to be true and certain, avail, when innumerable experiments have produced nothing like it? However, fome men are infected with an incurable itch of writing, and take great pleasure in contradicting others, to whom they bear envy. Let us therefore give them leave to applaud themselves, and enjoy their own vainglory.

But they will still go on to terrify us, by faying, that there is danger left, together with the fmall-pox, fome other infectious difeafe, inherent in the blood and humours of the fick perfon, fhould be tranfmitted into the found body; all contagion being very fubtile,

U 2

Chap. V fubtile, and wonderfully active. And it is indeed not improbable, that fome other diftemper, befides thofe which are cutaneous, may, by fuch a way as this, get admittance into the fkin; and fuch perhaps are fcrophulous fwellings, and the venereal difeafe. Yet I can hardly believe, that it ever happens, that the feed of one distemper fhould bring along with it mixed, the procreative matter of another, of a nature quite different from it. However it be, it would be madness in a phyfician, without any choice, to take the morbid matter for this purpose, out of fick bodies, without diftinction. The most proper fubjects are infants or children, found in all other refpects, as far as can be judged, and borb of healthy parents. Besides, it is, in my opinion, more material, into what kind of a body the venom be infufed, than out of what it be taken. And this I the rather mention, because I have more than once known rafh and unwary furgeons to implant the difeafe into bodies weak, and of an ill habit, with a fatal event. Laftly, it is of very great confequence to take care not to throw a new infection into one already infected: for I have obferved this to prove mortal; nature being oppreffed and finking under a double difeafe, when perhaps fhe might have got the better of either of them fingle.

I have often considered for what reasons it is, that the inoculated is fafer than the natural fmall-pox; and the following feem to be the chief. Firft, the venom is communicated to a young, healthy, and, for the age, ftrong body. In the next place, the violence of the fever, which follows, is prevented, if there be occafion, by bleeding, and gentle purging. And

laftly,

laftly, through the whole time that the contagious matter is exerting its malignity upon the humours (which is generally eight or nine days), quietnefs, moderation in diet, and every thing elfe is ftrictly obferved: whereas, many incur the natural diftemper on a fudden, when the blood is heated with wine and exercife; by which means, all the fymptoms must neceffarily prove more fevere and dangerous. Some have also been of opinion, that the difcharge out of the wound made to introduce the purulent matter, and likewife from the fmall pimples which break out round it, may contribute fomething to the fafety of the patient. But the fmall quantity which runs out this way, cannot, I think, avail much. Two blifters laid, one to an arm, the other to a leg, will certainly do much more; efpecially if they be kept running throughout the whole courfe of the difeafe. And I make no queftion, but this practice would be of ver ry great fervice.

It is proper to mention, that this artificial difeafe is ufually fo mild, that it fcarce requires any help from medicines. But where it happens otherwife, as it fometimes does, the fame will be neceffary, which have been directed in the feveral kinds of the natural fmall-pox.

To conclude; it ought not to be omitted, that boils, and fwellings under the ears, and in the armpits, arife more frequently after the diftemper procured by art, than after that which comes of its own accord; for this reafon, as I fuppofe, that the venomous matter is pushed forward with lefs force, which difadvantage nature makes amends for this way.

Therefore, all poffible means are to be used to

ripen fuch tumours, of whatever kind they are: if this cannot be done, they must be opened by incifion; and when all the matter is drawn out, the body must be purged by proper medicines, which are to be oftener repeated in this, than in the natural difeafe.

THEO

CHAP. VI.

Of the measles.

HE measles have a great affinity with the fmallpox; being originally bred in the fame country, propagated in the fame manner, by infection, into diftant parts of the world, and never feizing any perfon more than once.

The hiftory of this disease, as it generally appears among us, Dr Sydenham has defcribed with his ufual accuracy, calling it a fever, which in its nature and method of cure agrees very much with the smallpox; that is, accompanied with a great inflammation, and in which puftules of a particular kind are thrown out upon the skin.

Now, this inflammation does not only affect the furface of the body, but the inner parts alfo, and par ticularly the lungs : hence follows a cough, with a difficulty of breathing. And although the diftemper in its nature be lefs dangerous than the fmall pox, and continues a fhorter time; for it ufually is ended in fix or feven days, or, at the fartheft, in eight, very thin, and light fcales, like fine flower, falling off from the skin at that time; yet it feizes with more violent

heat,