The fact of psychical sexual differences -- Attempts to deny their existence -- Rosa Mayreder’s “Critique of Femininity” -- The sexual nuances of the psyche -- Ineradicability of these -- Condemnation of psychical bisexuality -- Expression of psychical difference in the demeanour of the sperm cell and the germ cell -- Original representatives of the differing natures of man and woman -- Recent researches regarding psychical sexual differences -- Sensory sensations -- Intellectual differences -- Experiments of Jastrow, Minot, and others -- Inquiries of Delaunay and Havelock Ellis -- Readier suggestibility of women -- Tendencies to independent activity on the part of women -- Higher spiritual activities in man and woman -- Woman’s talent for politics -- Emotivity of woman -- Greater susceptibility to fatigue -- Decline of emotivity in the modern woman -- Artistic talents of man and woman -- Greater variability of man -- Influence of menstruation on the feminine physique -- Psychological experiments of H. B. Thompson -- Woman and man heterogeneous natures -- Comparison by Alfons Bilharz -- The enigmatical in woman -- Poets and thinkers on this question -- A saying of Theodor Mundt -- Antipathy of the sexes -- Love as the solution of the enigma -- Significance of psychical differences for the woman’s question -- Part played by women in civilization -- Retrospect of primeval history -- Women as the discoverers of handicrafts and arts -- As the teachers of man -- Thomas Henry Huxley on the woman’s question -- The value of work for woman -- Improvement of domestic service according to Schmoller -- The woman of the future. _Appendix: Sexual Sensibility in Woman._ -- An old topic of dispute -- Sexual sensibility in man -- Feminine erotic types -- Theory of Lombroso and Ferrero -- Adler’s monograph -- Refutation of the theory of the lesser sensual sensibility of woman -- Diffuse character of the feminine sexual sphere -- Researches of Havelock Ellis regarding the sexual impulse in woman -- Experience of alienists regarding sexuality in woman -- A case of temporary sexual anæsthesia -- Causes of sexual frigidity. CHAPTER V The unquestionably existing physical differences between the sexes respectively, correspond equally without question to existing =psychical= differences. Psychically, also, man and woman are completely =different= beings. We must not employ the word “psychical,” as it is so often employed, in the sense of pure “intelligence”; we must understand the term to relate to the entire conception and content of the psyche, to the whole spiritual being--the spiritual habitus, emotional character, feelings, and will: we shall then immediately be convinced that masculine and feminine beings differ through and through, that they are heterogeneous, incomparable natures.