Every medicine exhibits peculiar actions on the human frame, which are not produced in exactly the same manner by any other medicinal substance of a different kind.1
1 This fact was also perceived by the estimable A. v. Haller, who says (Preface to his Hist. stirp. helv.): Latet immensa virium diversitas in iis ipsis plantis, quarum facies externas dudum novimus, animas quasi et quodcunque caelestius habent, nondum perspeximus.