Every phase of the sexual life of woman, from the threshold of puberty to the extinction of sexual activity, the first appearance of menstruation, the complete development of the sexual organs, the act of copulation, conception, pregnancy, parturition, and the puerperium, finally the involutionary process which accompanies the cessation of menstruation at the climacteric period—every one of these sexual phases entails consecutive physiological processes and pathological changes alike in the individual organs and in the nutritive condition of the entire organism, in the functions of the cardio-vascular apparatus, of the brain and the nerves, of the skin and the sense-organs, in the processes of digestion and general metabolism. Herein we see a striking illustration of the old saying of _von Helmont_, _propter solum uterum mulier est quod est_;[10] also of the similar aphorism of _Hippocrates_, _uterus omnium causa morborum qui mulieres infestant_;[11] a conception summed up by _Goethe_ in the words of Mephistopheles: “Es ist ihr ewig Weh und Ach So tausendfach Aus einem Punkte zu kurieren.” Just as in a tree the process of growth is made manifest to the superficial observer by the pleasure he feels at the sight of the buds and blossoms, by the refreshment he obtains from the fruit, and by the sadness which the withering of the leaves causes him, so in the sexual life of woman there are landmarks which no one can possibly overlook, by means of which three great epochs are distinguished. These are: puberty (the menarche), recognized by the first appearance of menstruation and the awakening of the sexual impulse; sexual maturity (the menacme), in the fully developed woman, characterized by the functions of copulation and reproduction; and sexual involution (the menopause), in which we see the gradual decline and ultimate extinction of sexual power and all its manifestations. In all these three epochs the sexual life of woman not only affects the hidden domain of the genital organs, but controls also all the vegetative, physical, and mental processes of the body, and is clearly and incontestably apparent in all vital manifestations. What Madame de Staël said of love is indeed true of the entire sexual life of woman: _l’amour n’est qu’unc épisode de la vie de l’homme; c’est l’histoire tout entière de la femme_.[12]. The sexual life of woman is coextensive with the peculiar vital activity of the female sex, for it endures from the moment when individuality first begins to develop out of the indifferent stage of childhood until the decline into the dead-level of senility.