7 O A VIS INERTIAE

the animal œconomy; the motion of th t bloodand other f.uids, the action of the muscles , ofthe stomach , hearts guts-, in a word, everymaterial action as material, and excluding theextraneous impulse of any immaterial agent,supposes re-action and resistance to make itconceivable. I can as well conceive that theshadow of my hand could wield, and movethe pen while I write, as that my hand coulddo it, if the parts of it had no resistance.Therefore, whatever principle or hypothesistakes away resistance and re-action from mat-ter, destroys affiionx tfelf, and, in effect the na-ture of matter 5 for, as resistance supposes so-lidity; so contrarily, solidity supposes resist-ance; or, because the parts cannot yield toeach other, therefore they must resist. Thislets us fee where resistance is ultimately lodg-ed, and whence only it can be derived ; itsprings from solidity , and traced backward isfound seated there. And this way also weagain fee, that upon the supposition thatmatter did not resist or re-act, that is, in ef-fect, did not act, the organized body of ananimal, or plant, (where there is a circula-tion of action and re-action, as well as of mo-tion) would have been a thing impossible,as hath been observed before (N° 8 and 22.)

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