continuance [Errata: contrivance] of the small parts of Bodies. For 'tis by motion that one part of matter acts upon another; and 'tis, for the most part, the texture of the Body upon which the moving parts strike, that modifies to motion or Impression, and concurrs with it to the production of those Effects which make up the chief part of the Naturalists Theme. [Footnote 25: _De Cons. & dissen. cap. 11. pag. 186._] [Footnote 26: _Sennert. de Con. seus. [Transcriber's Note: Consens.] & Dissens. pag. 165. 166._] But (sayes _Eleutherius_) me thinks for all this, you have left some part of what I alledg'd in behalf of the three principles, unanswer'd. For all that you have said will not keep this from being a useful Discovery, that since in the Salt of one Concrete, in the Sulphur of another and the Mercury of a third, the Medicinal vertue of it resides, that Principle ought to be separated from the rest, and there the desired faculty must be sought for. I never denyed (Replyes _Carneades_) that the Notion of the _Tria Prima_ may be of some use, but (continues he laughing) by what you now alledg for it, it will but appear That it is useful to Apothecaries, rather than to Philosophers, The being able to make things Operative being sufficient to those, whereas the Knowledge of Causes is the Thing looked after by These. And let me Tell You, _Eleutherius_, even this it self will need to be entertained with some caution. For first, it will not presently follow, That if the Purgative or other vertue of a simple may be easily extracted by Water or Spirit of Wine, it Resides in the Salt or Sulphur of the Concrete; Since unlesse the Body have before been resolved by the Fire, or some Other Powerful Agent, it will, for the most part, afford in the Liquors I have named, rather the finer compounded parts of it self, Than the Elementary ones. As I noted before, That Water will dissolve not only pure Salts, but Crystals of Tartar, Gumme Arabick, Myrr'h, and Other Compound Bodies. As also Spirit of Wine will Dissolve not only the pure Sulphur of Concretes, but likewise the whole Substance of divers Resinous Bodies, as Benzoin, the Gummous parts of Jallap, Gumme Lacca, and Other bodies that are counted perfectly Mixt. And we see that the Extracts made either with Water or Spirit of Wine are not of a simple and Elementary Nature, but Masses consisting of the looser Corpuscles, and finer parts of the Concretes whence they are Drawn; since by Distillation they may be Divided into more Elementary substances.