[67] L'Hygiène sexuelle et ses Conséquences morales, p. 26, Paris, 1895.
[68] Jacobus X——, Lois Génitales, p. 16, Paris, 1906.
[69] Albert Moll, Untersuchungen über die Libido Sexualis (Studies concerning the Sexual Impulse), p. 256 et. seq., Berlin, 1897.
[70] Émile (at the beginning of Book IV.).
[71] Magister Laukhards Leben und Schicksale, von ihm selbst beschrieben, bearbeitet von Viktor Petersen (The Life and Fortunes of Master Laukhard, described in his own words, and edited by Viktor Petersen), vol. i. p. 15, Stuttgart, 1908.
[72] Monsieur Nicolas, vol. i. p. 51, Paris (Liseux), 1884.
[73] Kinderleben in der deutschen Vergangenheit (Child Life in Old Germany), p. 112, Leipzig, 1900.
[74] Die geschlechtlich-sittlichen Verhältnisse der evangelischen Landbewohner im Deutschen Reiche, dargestellt auf Grund der von der Allgemeinen Konferenz des deutschen Sittlichkeitsvereine veranstalteten Umfrage (The State of Sexual Morality among the Protestant Inhabitants of the German Empire, as shown by an Inquiry instituted by the General Conference of the German Societies for the Promotion of Public Morals), vol. ii pp. 562-3, Leipzig, 1897. The collective investigation made by Wagner, Wittenberg, and Hückstädt, as a part of the inquiry instituted by the General Conference of the German Societies for the Promotion of Public Morals, is certainly the most exhaustive of which any record at present exists.
[75] Wie der Geschlechtstrieb des Menschen in Ordnung zu bringen usw. (How to Control the Human Sexual Impulse, &c.), Brunswick, 1791.
[76] Studies in the Psychology of Sex, vol. iii.; Analysis of the Sexual Impulse, pp. 59-60 and footnote, Davis, Philadelphia, 1908.