A small degree of attention will be sufficient to perceive, that Sauvages, by this just distinction, actually separates this kind of tremulous motion, and which is the kind peculiar to this disease, from the Genus Tremor. In doing this he is fully warranted by the observations of Galen on the same subject, as noticed by Van Swieten[5]. “Binas has tremoris species[6] Galenus subtiliter distinxit, atque etiam diversis nominibus insignivit, tremor enim (τϱὁμ &) facultatis corpus moventis et vehentis infirmitate oboritur. Quippe nemo, qui artus movere non instituerit tremet. Palpitantes autem partes, etiam in quiete fuerint, etiamsi nullum illis motum induxeris palpitant. Ideo primam (_posteriorem_) modo descriptam tremoris speciem, quando quiescenti homini involuntariis illis et alternis motibus agitantur membra, palpitationem (πἁλμον) dixit, posteriorem (_primam_) vero, quæ non fit nisi homo conetur partes quasdam movere tremorem vocavit.” [Footnote 5: Comment, in Herman. Boerhaav. Aphorismos. Tom. ii. p. 181.] [Footnote 6: De tremore. Cap. 3 and 4. Chart, Tom. vii. p. 200-201.] Under this authority the term palpitation may be employed to mark those morbid motions which chiefly characterise this disease, notwithstanding that this term has been anticipated by Sauvages, as characteristic of another species of tremor[7]. The separation of palpitation of the limbs (_Palmos_ of Galen, _Tremor Coactus_ of de la Boë) from tremor, is the more necessary to be insisted on, since the distinction may assist in leading to a knowledge of the seat of the disease. It is also necessary to bear in mind, that this affection is distinguishable from tremor, by the agitation, in the former, occurring whilst the affected part is supported and unemployed, and being even checked by the adoption of voluntary motion; whilst in the latter, the tremor is induced immediately on bringing the parts into action. Thus an artist, afflicted with the malady here treated of, whilst his hand and arm is palpitating strongly, will seize his pencil, and the motions will be suspended, allowing him to use it for a short period; but in tremor, if the hand be quite free from the affection, should the pen or pencil be taken up, the trembling immediately commences. [Footnote 7: Sect. XVI. _Tremor palpitans_, Preysinger classis morborum. _Palmos_ Galeni. In tremoribus vulgaribus, æqualibus temporum intervallis, non musculus, sed artus ipsemet alternatim attollitur aut deprimitur, aut in oppositas partes it atque redit per minima tamen spatiola; in palpitatione verò sine ullo ordine musculi unius lacertus subito subsilit, nec regulariter continuoque movetur, sed nunc semel aut bis, nunc minimé intra idem tempus subsilit; an causa irritans in sensorio communi, an in musculo ipse palpitante Quærenda sit, ignoramus. _Nosologiæ Methodicæ_, Vol. I. p. 559. 1768.