Befides, it is eafy to fhew how the air, by the fenfible ill qualities discoursed of in the last chapter, fhould favour infectious difeafes, by rendering the body obnoxious to them. Indeed other hurtful qualities of the air are more to be regarded than its heat alone: for the plague is fometimes ftopt, while the heat of the feafon increafes, upon the emendation of the air in other refpects. At Smyrna the plague, which is yearly carried thither by ships, conftantly ceases about the 24th of June, by the dry and clear weather they always have at that time; the unwholefome damps being then diffipated that annoy the country in the fpring. However, the heat of the air is of fo much confequence, that if any fhip brings it in the winter-months of November, December, January, or February, it never fpreads; but if later in the year, as in April or afterwards, it continues till the time before mentioned. But moreover, what was faid before of fome latent diforders in the air having a fhare in fpreading the plague, will likewise have place in these countries; as the last plague in the city of London remarkably proves, the feeds of which, upon its firft entrance, and while it was confined to a houfe or two, preferved themfelves through a hard frofty winter, and again put forth their malignant quality as foon as the warmth of the fpring gave them force but, at the latter end of the next winter, they were fuppreffed fo as to appear no more, though in the month of December more than half the parishes of the city were infected. A corrupted state of air is, without doubt, neceffary to give these contagious atoms their full force; for otherwise, it were not eafy to conceive how the plague, when once it had feized any place, fhould ever ceafe but with the deftruction of all the inhabitants which is readily accounted for by fuppofing an emendation of the qualities of the air, and the restoring of it to a healthful state capable of diffipating and fuppreffing the malignity. : On the other hand, it does not appear, that the air, however corrupted, is ufually capable of carrying infection to a very great distance; but that commonly the plague is fpread from town to town by infected perfons and goods for there are numberlefs inftances where the plague has caufed a great mortality in towns, while other towns and villages, very near them, have been entirely free. And hence it is, that the plague fometimes fpreads from place to place very irregularly. Thuanus * fpeaks of a plague in Italy, which one year was at Trent and Verona, the next got into Venice and Padua, leaving Vicenza, an intermediate place, untouched, though the next year that alfo felt the fame ftroke: a certain proof that the plague was not carried by the air from Verona to Padua and Venice; for the infected air must have tainted all in its paffage. We have had lately in France one inftance of the fame nature, when the plague was carried at once out of Provence feveral leagues into the Gevaudan. Ufually indeed the plague, especially when more violent than ordinary, fpreads from infected places into thofe which border upon them which probably is fometimes effected by fome little communication infected towns are obliged to hold with the country about them for the fake of ne*Hiftor. lib. lxii, ceffaries, ceffaries, the fubtilty of the venom now and then eluding the greatest precautions; and at other times by fuch as withdraw themfelves from infected places into the neighbourhood. I own it cannot be demonftrated, that when the plague makes great ravage in any town, the number of fick fhall never be great enough to load the air with infectious effluvia, emitted from them in fuch plenty, that they may be conveyed by the winds into a neighbouring town or village, without being difperfed so much as to hinder their producing any ill effects; efpecially fince it is not unufual for the air to be fo far charged with these noxious atoms, as to leave no place within the infected town fecure: infomuch that when the diftemper is at its height, all fhall be indifferently infected, as well thofe who keep from the fick, as thofe who are near them; though, at the beginning of a plague, to avoid all communication with the difeafed, is an effectual defence. However, I do not think this is often the cafe juft as the fmoke with which the air of the city of London is constantly impregnated, efpecially in winter, is not carried many miles diftant; though the quantity of it is vaftly greater than the quantity of infectious effluvia, that the most mortal plague could generate. But, to conclude what relates to the air, fince the ill qualities of it in these northern countries are not alone fufficient to excite the plague, without imported contagion, this thews the errour of a common opinion, countenanced by authors of great name *, that we are neceffarily vifited with the plague once in thirty or forty years which is a mere fancy, without * Sydenham de peste. foundation foundation either in reafon or experience; and therefore people ought to be delivered from fuch vain fears. Since the peftilence is never originally bred with us, but always brought accidentally from abroad, its coming can have no relation to any certain period of time. And although our three or four laft plagues have fallen out nearly at fuch intervals, yet that is much too short a compafs of years to be a foundation for a general rule. Accordingly we fee that almost fourscore years have paffed over without any calamity of this kind. The air of our climate is fo far from being ever the original of the true plague, that moft probably it never produces thofe milder infectious diftempers, the finall-pox and measles. For thefe diseases were not heard of in Europe before the Moors had entered Spain and (as I have obferved in the preface) they were afterwards propagated and spread through all nations, chiefly by means of the wars with the Sa racens. Moreover, we are fo far from any neceffity of these periodical returns of the plague, that, on the contrary, though we have had several strokes of this kind, yet there are inftances of bad contagions from abroad being brought, over to us, which have proved lefs malignant here, when our northern air has not been difpofed to receive fuch impreffions. The fweating fickness, before hinted at, called Sudor Anglicus and Febris Ephemera Britannica, becaufe it was commonly thought to have taken its rife here, was most probably of a foreign original: and though not the common plague with glandular tumours, and carbuncles, yet a real peftilence from the fame fame caufe, only altered in its appearance, and abated in its violence, by the falutary influence of our climate. For it preserved an agreement with the common plague in many of its fymptoms, as exceffive faintnefs and inquietudes, inward burnings, &c. thefe fymptoms being no where observed in fo intense a degree as here they are defcribed to have been, except in the true plague: and, what is much more, it was likewife a contagious disease. The first time this was felt here, which was in the year 1485, it began in the army with which King Henry VII. came from France and landed in Wales and it has been fuppofed by fome to have been brought from the famous fiege of Rhodes by the Turks three or four years before, as may be collected from what Dr Keyes fays in one place of his treatife on this disease +. Befides, of the several returns which this has made fince that time, viz. in the years 1506, 1517, 1528, and 1551, that in the year 1528 may very juftly be fufpected to have been owing to the common peftilence, which at thofe times. raged in Italy, as I find one of our hiftorians has long ago conjectured and the others were very probably from a Turkish infection. If at least fome of these returns were not owing to the remains of former attacks, a fuitable conftitution of air returning to put the latent feeds in action before they were quite deftroyed. It is the more probable that this * Vid. Caium de febr. ephemer. Britan. and Lord Bacon's hiftory of Henry VII. + Pag. 162. edit. Vid. Rondinelli contagio in Firenze, Lord Herbert's Lovan. & Summonte hiftor. di Napoli. history of Henry VIII. difeafe |