[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 Mueller 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 Misere en Chine_, "Les
Eunuques du Palais Imperial de Pekin," 1901.

[11] P. Marie, "Eunuchisme et Erotisme," _Nouvelle Iconographie de la
Salpetriere_, 1906, No. 5, and _Progres medical_, 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
Gynaecological Journal_, August, 1902; W.G. Bridgman, _Medical Standard_,
1896; J.M. Cotterill, _British Medical Journal_, April 7, 1900 (also
private communication); Paul F. Munde, _American Journal of Obstetrics_,
March, 1899.

[16] See Swale Vincent, _Internal Secretion and the Ductless Glands_,
1912; F.H.A. Marshall, _The Physiology of Reproduction_, 1910, ch. ix;
Munzer, _Berliner klinische Wochenschrift_, Nov., 1910; C. Sajous, _The
Internal Secretions_, vol. i, 1911. The adrenal glands have been fully and
interestingly studied by Glynn, _Quarterly Journal of Medicine_, Jan.,
1912; the thyroid, by Ewan Waller, _Practitioner_, Aug., 1912; the
internal secretion of the ovary, by A. Louise McIlroy, _Proceedings Royal
Society Medicine_, July, 1912. For a discussion at the Neurology Section
of the British Medical Association Meeting, 1912, see _British Medical
Journal_, Nov. 16, 1912.

[17] Since this was written I have come across a passage in _Hampa_ (p.
228), by Rafael Salillas, the Spanish sociologist, which shows that the
analogy has been detected by the popular mind and been embodied in popular
language: "A significant anatomico-physiological co