At the time of puberty the infantile uterus undergoes changes affecting both its external form and the shape of its interior cavity. The body of the uterus enlarges to the size characteristic of sexual maturity, and its mucous membrane becomes the seat of periodic changes. This waxing and waning growth and transformation of the uterine mucous membrane continues throughout the period of menstrual activity, the most superficial layers of the membrane being shed during menstruation, a process followed by regeneration, which is itself succeeded by the premenstrual thickening. When conception occurs, still more extensive changes ensue, the fertilized ovum becoming imbedded in the uterine mucous membrane, and the pregnant uterus, in shape and structure and in the respective relations of the body and neck of the organ, in the increasing distension of its veins and the increasing size of its nerves, becoming adapted to the important functions it has now to fulfil. When these have been fulfilled, and, parturition having taken place, the uterus is empty once more, the organ again adapts itself to altered circumstances by the process of involution. Later, in the climacteric period, a slow regressive process occurs, the outward manifestation of which is the cessation of the menstrual flow, characterized anatomically by atrophy of the muscular tissue of the uterus and of its vascular apparatus, by the dessication of its mucous membrane, by obliteration of the lumen of the uterine cavity, and ultimately by senile degeneration and atrophy of the now entirely functionless organ, so that it becomes an insignificant, cicatrized, solid body. Next to the ovaries and the uterus, it is the pelvic fascia which in its entire architectonic structure as well as in its individual parts undergoes the most notable changes in consequence of the processes of generation. A short account of the nerves and blood vessels of the female genital organs appears indispensable, to facilitate the comprehension of the manner in which sexual processes are influenced by the nervous system, and to demonstrate the intimate connection between the blood-supply of the genital apparatus and the general circulation. The complex nervous network of the female sexual organs is supplied by spinal as well as by sympathetic fibres, the fibres from the two systems anastomosing in a very intimate manner. [Illustration: