BUT there is something yet further, besides particular Constitutions of Air, that is taken Notice of by Physicians, as a general Cause of Maladies of this kind; and that is what is commonly called _Contagion_ or _Infection_; by this Term _Contagion_, is understood a Disease arising from the Contact of such Bodies or Particles as have in them a Power of Altering the due Crasis of a healthful Person, and inducing still one common Disease; these Particles are generally called by Physical Writers μιασματα, _Contagiosa_, or _Contagij Seminia_; and the Difference of Pestilences arising from these Causes seems much to differ from what have been hitherto taken Notice of, as the former cannot be shunned but by quite leaving the diseased Climate, or by such a Strength, or Turn of Constitution, as resists, or yeilds not to the general Disorder; whereas in this last Case, a Person seems to be equally safe in any Air that is not impregnated with these contagious _Effluvia_, and the greatest Danger arises from the Nearness to diseased Persons, or whatsoever else is capable of harbouring those mischievous and secret Messengers, as the Poet[41] takes Notice. _Quo proprior quisq; est, servitq; fidelius agro In partem Lethi citius venit.————_ THE Histories of Physick abound with Relations of Pestilences from no other Cause than what arises from the Importation of the Disease, if it may be so termed, from distant Countries; and sometimes not by Persons themselves distempered, but by the Conveyance of these _Pestilential Miasmas_ in their Cloaths or Wares imported in the Way of Trade. _Fracastorius_,[42] an eminent _Italian_ Physician, tells us, That in the Year Fifteen Hundred and Eleven, when the _Germans_ were in Possession of _Verona_, there arose a deadly Disease amongst the Soldiers from the Wearing only a Coat purchased for a small Value; for it was observed, that every Owner of it soon sickened and died; until, at last, the Cause was so manifestly from some Infection in the Coat, that it was ordered to be burned. Ten Thousand Persons, he says, were computed to fall by this Plague before it ceased.