[3] Féré, "La Prédisposition dans l'étiologie des perversions sexuelles," _Revue de médecine_, 1898. In his more recent work on the evolution and dissolution of the sexual instinct Féré perhaps slightly modified his position by stating that "the sexual appetite is, above all, a general need of the organism based on a sensation of fullness, a sort of need of evacuation," _L'Instinct sexuel_, 1899, p. 6. Löwenfeld (_Ueber die Sexuelle Konstitution_, p. 30) gives a qualified acceptance to the excretory theory, as also Rohleder (_Die Zeugung beim Menschen_, p. 25). [4] Goltz, _Centralblatt für die med. Wissenschaften_, 1865, No. 19, and 1866, No. 18; also _Beiträge zur Lehre von den Funktionen des Frosches_, Berlin, 1869, p. 20. [5] J. Tarchanoff, "Zur Physiologie des Geschlechtsapparatus des Frosches," _Archiv für die Gesammte Physiologie_, 1887, vol. xl, p. 330. [6] E. Steinach, "Untersuchungen zur vergleichenden Physiologie der männlicher Geschlechtsorgane insbesondere der accessorischen Geschlechtsdrüsen," _Archiv für die Gesammte Physiologie_, vol. lvi, 1894, pp. 304-338. [7] See, e.g., Shattock and Seligmann, "The Acquirement of Secondary Sexual Characters," _Proceedings of the Royal Society_, vol. lxxiii, 1904, p. 49. [8] For facts bearing on this point, see Guinard, art. "Castration," Richet's _Dictionnaire de Physiologie_. The general results of castration are summarized by Robert Müller in ch. vii of his _Sexualbiologie_; also by F.H.A. Marshall, _The Physiology of Reproduction_, ch, ix; see also E. Pittard, "Les Skoptzy," _L'Anthropologie_, 1903, p. 463. [9] For an ancient discussion of this point, see Schurig, _Spermatologia_, 1720, cap. ix. [10] J.J. Matignon, _Superstition, Crime, et Misère en Chine_, "Les Eunuques du Palais Impérial de Pékin," 1901. [11] P. Marie, "Eunuchisme et Erotisme," _Nouvelle Iconographie de la Salpêtrière_, 1906, No. 5, and _Progrès médical_, Jan. 26, 1907. [12] _Pedagogical Seminary_, July, 1897, p. 121. [13] See, for instance, the case reported in another volume of these _Studies_ ("Sexual Inversion"), in which castration was performed on a sexual invert without effecting any change. [14] Guinard, art. "Castration," _Dictionnaire de Physiologie_. [15] M.A. Colman, _Medical Standard_, August, 1895; Clara Barrus, _American Journal of Insanity_, April, 1895; Macnaughton-Jones, _British Gynæcological Journal_, August, 1902; W.G. Bridgman, _Medical Standard_, 1896; J.M. Cotterill, _British Medical Journal_, April 7, 1900 (also private communication); Paul F. Mundé, _American Journal of Obstetrics_, March, 1899.