Thefe, in my opinion, always exifted in their refpective native places, as proceeding from the fame natural caufes perpetually exerting themselves.

It is found by experience, that fome of these are contagious, and that the contagion is frequently propagated to very remote countries by means fuitable to the nature of this or that disease. For fome not only communicate the infection by immediate contact of the found with the morbid body, but have fuch force, that they spread their pernicious feeds by emitting very fubtile particles; which lighting on foft fpongy fubftances, fuch as cotton, wool, raw-filk, and cloathing, penetrate into them, and there remain pent up for a confiderable time in the fame manner as I have elsewhere accounted for the wide progrefs of the plague from Africa its original country *. Others, on the contrary, are infectious by contact alone. Wherefore the firft fort may be fpread by commerce, but the latter by cohabitation only.

Of this kind is the venereal difeafe; which, according to hiftorians of the moft undoubted credit, is a native of fome of the American iflands, efpecially Hifpaniola, and was brought over into Spain near the end of the fifteenth century: thence, in the year 1495, it was carried to Naples, during the war between Ferdinand of Arragon and the French, by fome Spanish troops, who had contracted it in the aforefaid ifland. For thefe and the French foldiers having at different times had communication with the fame women, according as the fame towns alternately fell into the hands of the two contending parties; this filthy difeafe firft fpread itself over the two armies, * Difcourfe on the plague, part i. chap. i.

thence

thence made its way into Italy, and has fince infected - moft parts of the habitable world *.

And I very well remember, that a certain English merchant, who had refided many years in Mufcovy, affured me, that the venereal difeafe was hardly known in that country before the reign of the late Czar Peter the Great becaufe till that time the traffic carried on by the Muscovites did not require much communication or dealing with foreigners. But after that emperour had taken the refolution of vifiting other parts of Europe, and had fent many of his fubjects abroad to learn trades and manufactures; these carried back with them the dire effects of their unlawful luft into their native country; which raged there with the greater feverity, as inflammations and ulcers are the more difficult to be cured in cold climates.

But to return to the fmall-pox: I really take this disease to be a plague of its own kind, which was originally bred in Africa, and more especially in Æthiopia, as the heat is exceffive there; and thence, like the true plague, was brought into Arabia and Egypt after the manner above mentioned.

Now, if any one should wonder why this contagion was fo long confined to its native foil, without fpreading into diftant countries: I pray him to confider, that foreign commerce was much more fparingly carried on in ancient times, than in our days, efpecially between mediterranean nations; and likewife, that the ancients feldom or never undertook long voyages by fea, as we do. And Ludolfus obferves that the Ethiopians in particular were ignorant of

* Vid. Aftruc de morbis venereis, lib. i. cap. 10. II.

mercantile affairs*. Therefore, when in procefs of time the mutual intercourfe of different nations became more frequent by wars, trade, and other caufes; this contagious difeafe was fpread far and wide. But towards the end of the eleventh century, and in the beginning of the twelfth, it gained vast ground, by means of the wars waged by a confederacy of the Chriftian powers against the Saracens, for the recovery of the Holy Land; this being the only vifible recompenfe of their religious expeditions, which they brought back to their respective countries. From that time forward, wherefoever this most infectious diftemper once got a footing, there it has obftinately held uninterrupted poffeffion. For the purulent matter, which runs out of the puftules, being caught in the bed-cloaths and wearing apparel of the fick, and there drying, and remaining invifible, becomes a nursery of the disease, which foon breaks forth on those who happen to come in contact with it; especially, if the feafon of the year, and state of the air, be favourable to its action.

In this place, it may not be improper, in confirmation of the foregoing doctrine, to relate the following fact, which was attefted to me by a gentleman of great experience, who had been for many years governour of Fort St George in the Eaft Indies. While he was in that poft, a Dutch fhip put into the Cape of Good Hope, fome of the crew of which had had the fmall-pox in the voyage thither. The natives of that country, who are called Hottentots, are fo wild and stupid, that they might feem to be of a middle fpecies between men and brutes; and it is their cu* Hift. Æthiop. lib. iv. cap. 7.

ftom

ftom to do all fervile offices for the failors who land there. Now, it happened, that fome of thefe miferable wretches were employed in washing the linen and cloaths of thofe men who had had the diftemper : whereupon they were feized with it, and it raged among them with fuch violence, that most of them perished under it. But as foon as fatal experience had convinced this ignorant people, that the difeafe was fpread by contagion, it appeared, that they had natural fagacity enough to defend themfelves. For they contrived to draw lines round the infected part of their country, which were so strictly guarded, that, if any perfon attempted to break through them, in order to fly from the infection, he was immediately fhot dead. Now, this fact feems the more remarkable, as it evinces, that neceffity compelled a people of the moft grofs ignorance and ftupidity to take the fame measure, which a chain of reafoning led us formerly to propose, in order to stop the progress of the plague *; and which, fome time after, had a happy effect, not only in checking, but even entirely extinguishing that dreadful calamity in France, where it broke forth, and threatened the rest of Europe with deftruction.

CHA P. II.

Of the nature and forts of the fmall-pox.

HAving fufficiently proved, in the preceding chap

ter, that the fmall-pox is a difeafe of the pestilential tribe; in order to a clearer knowledge of its * Difcourfe on the plague, part ii. chap. 2.

nature,

nature, I will briefly premife my notions of pesti

lence.

All fevers which attack the whole body, may be conveniently ranged under the three general heads of fimple, putrid, and peftilential.

Simple fevers arife from a long-continued excess of velocity in the motion of the blood, and its confequences, a disturbance of its due mixture, and an interruption of the fecretion of the humours in the feveral parts of the body.

Putrid fevers are caufed, when, together with a concurrence of these circumstances, a lentor enfues in the capillary blood-veffels; and as this fizy blood is gradually pushed forward by the force of the circulation into the veins, it there becomes putrid, and impregnates the rest of the mafs with a malignant quality, which is communicated both to the internal and external parts of the body.

Peftilential fevers, in fine, I call all thofe which are accompanied with fome fort of poifon. Now, of whatever nature this happen to be, it not only infects and corrupts the blood, but more particularly feizes on the fubtile nervous liquor, which is called the animal fpirits. Hence it is, that thefe fevers act with greater rapidity and violence, and are much more fatal than the other forts. But this one circumstance is common to all fevers, that nature endeavours to conquer the difeafe, by raifing fome struggle or ther, in order to throw forth from the body whatever is prejudicial to life.

Now, whereas the word nature is made ufe of by phyficians in the cure of all difeafes, I will here, once for all, plainly declare my fentiments of what

we