he perceived, intuitively, to be necessary to a full comprehension of his subject. But although the opinions and conjectures of this Treatise may, from the advanced state of anatomy and physiology, have but little intrinsic value, the method adopted by Aristotle may not be undeserving the attention of those who, with a wider range of special knowledge, are better prepared for the undertaking; unless, indeed, the Vital Principle is to be set down among those final causes, which, lying beyond the human comprehension, are to be admitted as ultimate facts. Although this may be the case, however, some interest must be taken in a Treatise which is, not only indicative of Aristotle's style and mode of argument, but pregnant also, by allusion, with collateral information.
This version has been made with the intention of rendering it, in so far as the analogies of language would allow, a faithful transcript of the opinions and manner of Aristotle; and notes are added for the elucidation of passages which by no periphrasis could be made intelligible to the general reader. It may be observed that the mind, (ὁ νοῦς), although nowhere defined, appears, in this Treatise, to represent the abstract immaterial principle usually attributed to the ψυχή ; for it alone is excluded from all direct participation in corporeal functions or changes.