A treatise of the small-pox and measles describing their nature, causes, and signs, diagnostick and prognostick, in a different way to what hath hitherto been known : together, with the method of curing the said distempers, and all, or most, of the best remedies : also, a particular discourse of opium, diacodium, and other sleeping medicines : with a reference to a very great case / by Gideon Harvey ...

CHAP. VI. Of Contagion, and contagious Diseases, of which the Small-Pox is a species.

1. TO make the marks of the abovementioned Phaenome∣non (which I may rather term a truth) to bear, it will be very ne∣cessary to premise a short Interloca∣tion concerning Contagious Diseases, which are all occasioned by exter∣nal adventitious particles, (effluvia, or miasmata) transmitted out of the ambient Air immediately, or me∣diately from other infectious bo∣dies.

2. These contagious particles be∣ing admitted through the pores, and by inspiration of the lungs into the Bodies of Animals, do in some few instantly, in most others after a greater or lesser interval of time exert their power, as is manifest in those that are infected with the

French Pox, whose effluvia or steams do in some operate soon after their admission, as appear by the starting up of venereal Symptoms in two, three, four, or more hours, even in others a moment after; but in many after a week, a month, three, four, five, or six months; a year, two, three, or four years; and in some old Bodies many years af∣ter.

3. It is universally observed, that many have received a pestilential Infection, which hath shewed its ma∣lignity in some instantly, in others some few hours, weeks, or months af∣ter; and this particularly is remarkt, that some having received into their Bodies pestilential particles at Con∣stantinople, did arrive many months after in Italy, where the said par∣ticles had put their malign powers into action, in that manner, that not only the transporter hath fallen into the Plague, but likewise hath infected other Bodies, who have so

filled the Air with pestiferous Mi∣asms, that the whole Country hath soon after fallen into the Plague; whence it is Italian Princes are so careful, that they will not suffer any person coming from those Le∣vant parts, to travel through their Country, or remain there, without having performed his quarantine, that is stay'd forty days in the La∣zaretto, where, if there be occasion, he must be purged and sweated, before they will allow him Prattica, that is, admit him to do his business in that Country.

4. I will only demand this Con∣cession, That all men who live in a pestiferous Air, must receive and admit by inspiration, and through the pores of their bodies, pestilential miasms, particles, or filaments, unless you do assert, That some men do not inspire deep enough, or theit Bodies are less pervious, and have fewer pores, and those possibly very narrow, contorted, or of a screw'd

figure, in which case they being de∣prived of a facil perspiration, or ra∣ther expiration, must always con∣tinue very weak and sickly; but these crazy and feeble persons are generally found to be chiefly subject to the Plague, which destroys your Assertion.

5. It is upon the certainty, or at least a strong presumption of the forementioned Concession, that Phy∣sicians do unanimously hold, there is no other infallible preserevative against the plague, but what is im∣plied in these three words, viz. Cito, Longe, & Tarde; in English, speedi∣ly, a long way off, and slow: that is, you must retire with all speed, remove to a far distance, and return very slow after the plague is ceased, left it should not intirely be extin∣guisht. By the way only; this fore∣mentioned Expedient being judged so infallible, doth evidently over∣throw the phantastic Notion, where∣by to explain the manner of agency

of sympathetic Remedies, viz. Vng. Armar. or Weapon-salve, calcined Vitriol, or sympathetic Powder, and such like asserting, there is a chain of crooked particles linkt together, that extends from those Remedies, being guided by the association of some of the Ulcers, or wounded par∣ticles on a Rag or Weapon, to the Ulcer or Wound it self, being pos∣sibly at a hundred miles more or less distance; which if true, would hold much more in pestiferous Miasms, that are spread over a small Region, or a great tract of Air; though it's very possible, that a cloud full of 'em may be driven by the wind to a far greater distance, even over the Seas, from one Country to another, but not by continuation in the man∣ner of chains extended to such a length; so that we are only to read such like Histories or Relations, as we do Romances, both being oft written with an adorned stile, as if they were true and real.