Numerous exact, scientific, ethnological, and psychological investigations concerning the sexes, among the most important of which we may mention those of Darwin, Allan, Münsterberg, C. Vogt, Ploss-Bartels, Jastrow, Lombroso and Ferrero, Shaw, Havelock Ellis, and Helen Bradford Thompson, have confirmed the existence of these differences in the nature of the two sexes. Many individual points still remain obscure, but the above-mentioned sexual difference is everywhere recognizable, and can never be entirely eradicated, even by a higher psychical differentiation. Even the author of the “Critique of Femininity,” who would open an unlimited perspective to the freedom of individuality, is still compelled to admit that the majority of women differ from men, no less in character than in intellect. Havelock Ellis, in his classical work “Man and Woman” (London, 1892), has given a summary of the psychical differences between the sexes, based upon the most recent anthropological and psychological investigations. This work forms the foundation for all later researches. Of the individual psychical phenomena in man and woman, the sensory sensations first demand consideration. In these no absolute and general superiority of one sex over the other can be shown to exist. The assumption that women have a more delicate power of sensory receptivity cannot be sustained; indeed, the contrary appears the truer view. It is true that women can be more readily excited by sensory stimuli, but they do not possess a more delicate sensory receptivity. As regards the general =intellectual endowment= of the sexes, the interesting experimental researches of Jastrow into the psychology of woman show that she possesses a greater interest in her immediate environment, in the finished product, in the decorative, the individual, and the concrete; man, on the other hand, exhibits a preference for the more remote, for that which is in process of construction or growth, for the useful, the general, and the abstract. In agreement with these views is a report in the _Berliner Städtischen Jahrbuch_ (1870, pp. 59-77), concerning the knowledge possessed by several thousands of boys and girls at the time of their entry into school. The report states: “The more usual, the more approximate, and the easier an idea is, the greater is the probability that the girls will excel the boys, and _vice versa_. In boys more frequently than in girls do we find that they know nothing of quite common things in their immediate environment.” Professor Minot arranged that persons of both sexes should cover ten cards with sketches of any subject they chose. It appeared from this experiment that the sketches of the men embraced a greater variety of subjects than those of the women.