What could Dr. _Mead_ mean by so gross an Oversight, in an Article, too, so material for _preventing_ pestilential Contagion? This Disposition, to be affected peculiarly by the Plague, is not neglected by _Hippocrates_, _Galen_, or any good Author of succeeding Ages; tho’ they had the same Reason to profess their Ignorance, as Dr. _Mead_ has to conceal his at this Time; for he is sure to make no Confession of this kind, howsoever it may otherwise appear. I hope he will not call this _a great Digression_, as we find he did formerly, on a like Occasion. _Fernelius_ declares, that it is very hard and difficult to know, what it is that renders every Body obnoxious to the Plague. And _Platerus_ makes this ingenuous Confession, That as I would gladly learn what this _Disposition_ of an Object may be; so I very readily confess, that I know nothing of it, though I am not ignorant, that this Poison acts very differently, according to the various Dispositions of the Body. And, what Hurt had it done Dr. _Mead_’s Character to have owned, That no _Agent_ can do any Thing without a fit _Disposition_ in the _Patient_? But, how dares he undertake to give Rules for preventing a Pestilence, and proceed in corrupting the Means of Knowledge that are common among other Physicians, and absolutely neglect this Disposition? It is for this Reason, that we hear them speaking another Language than Doctor _Mead_ does, even while they talk of what he calls his propagating Causes. Hear the excellent, and learned _Fracastorius_[8]. _Contagion_, says he, takes its Rise, often from the Air; it often passes from one Person to another; it is often receiv’d by a _Fomes_; and it sometimes has its first Origine and Beginning in _our selves_. Hence it is we find Dr. _Hodges_, in the common Language of Physicians, asserting, that [9]_four Things are necessary to a Contagion_. First, _That there is an Efflux of the contagious_ Seminium, _or_ Seed. Secondly, _That there is a convenient Medium for the contagious Particles to move through, and be conveyed by_. Thirdly, _A _Fitness_ in the _Subject_ to receive and cherish the contagious Effluvia_. _And_, Fourthly, _A due Stay of this Seminium_. So that it is much to be feared, that Dr. _Mead_ will suffer grievously in explaining his darling _Phenomena_, to which we are next to return; and no less in teaching us, _in the following Part of his Discourse_, how to prevent the silent Approaches of the Pestilence, and to suppress its Poison, if it should appear among us: All which he graciously promises to perform, and that in a newer and perfecter Method than was ever done before. [Footnote 8: Lib. 3. _de Morb. Contag._ cap. 7.] [Footnote 9: Page 52.]