[40] "The sensation of motion," Kline remarks ("The Migratory Impulse," _American Journal of Psychology_, October, 1898, p. 62), "as yet but little studied from a pleasure-pain standpoint, is undoubtedly a pleasure-giving sensation. For Aristippus the end of life is pleasure, which he defines as gentle motion. Motherhood long ago discovered its virtue as furnished by the cradle. Galloping to town on the parental knee is a pleasing pastime in every nursery. The several varieties of swings, the hammock, see-saw, flying-jenny, merry-go-round, shooting the chutes, sailing, coasting, rowing, and skating, together with the fondness of children for rotating rapidly in one spot until dizzy and for jumping from high places, are all devices and sports for stimulating the sense of motion. In most of these modes of motion the body is passive or semipassive, save in such motions as skating and rotating on the feet. The passiveness of the body precludes any important contribution of stimuli from kinesthetic sources. The stimuli are probably furnished, as Dr. Hall and others have suggested, by a redistribution of fluid pressure (due to the unusual motions and positions of the body) to the inner walls of the several vascular systems of the body." [41] _Anatomy of Melancholy_, part iii., sect. ii, mem. ii, subs. iv. [42] Sadger, "Haut-, Schleimhaut-, und Muskel-erotik," _Jahrbuch für psychoanalytische Forschungen_, Bd. iii, 1912, p. 556. [43] Marro (_Pubertà_, p. 367 et seq.) has some observations on this point. It was an insight into this action of dancing which led the Spanish clergy of the eighteenth century to encourage the national enthusiasm for dancing (as Baretti informs us) in the interests of morality. [44] It is scarcely necessary to remark that a primitive dance, even when associated with courtship, is not necessarily a sexual pantomime; as Wallaschek, in his comprehensive survey of primitive dances, observes, it is more usually an animal pantomime, but nonetheless connected with the sexual instinct, separation of the sexes, also, being no proof to the contrary. (Wallaschek, _Primitive Music_, pp. 211-13.) Grosse (_Anfänge der Kunst_, English translation, p. 228) has pointed out that the best dancer would be the best fighter and hunter, and that sexual selection and natural selection would thus work in harmony. [45] Féré, "Le plaisir de la vue du Mouvement," _Comptes-rendus de la Société de Biologie_, November 2, 1901; also _Travail et Plaisir_, ch. xxix. [46] Groos repeatedly emphasizes the significance of this fact (_Spiele der Menschen_, pp. 81-9, 460 et seq.); Grosse (_Anfänge der Kunst_, p. 215) had previously made some remarks on this point. [47] M. Kulischer, "Die Geschlechtliche Zuchtwahl bei den Menschen in der Urzeit," _Zeitschrift für Ethnologie_, 1876, p. 140 _et seq._ [48] Sir W.R. Gowers, _Epilepsy_, 2d ed., 1901, pp. 61, 138. [49] Guyon, _Leçons Cliniques sur les Maladies des Voies Urinaires_, 3d ed., 1896, vol. ii, p. 397.