After ejaculation and the removal of the genital congestion, the paralysis of the inhibitory centre ceases, and the normal nerve tonus of the blood vessels gradually reappears. The influx of blood into the genital vessels is thus cut off, and the erection of the corpora cavernosa ceases. Only the colliculus remains yet swelled, for some time. For this reason micturition is impossible immediately after ejaculation. After the act follows a state of exhaustion, weariness, weakness and inclination to sleep. Although the frantic condition and the semi-delirium generally lasts a short time only, still it is sufficiently long to exhaust completely the strength of the ordinary organism. After a certain time of rest, sex connection in a healthy person is followed by a joyous feeling and fresh vigor. The head feels more free and easy, the body more elastic, and a greater disposition to physical and intellectual labor results. CHAPTER VIII THE FUNCTIONS OF THE FEMALE GENITAL ORGANS _Functions of the ovary._—The ovary is lined by a layer of genital epithelia (“Keimepithel”), which undergo certain changes during the entire sexual life of the woman. The epithelia are continually transformed into ova. When a single genital epithelium leaves the ovarian lining to be transformed into an ovum it moves from the periphery toward the centre. It then surrounds itself with follicular epithelia and forms the Graafian follicle. Through its growth the Graafian follicle approaches again the periphery. All ripe Graafian follicles are, therefore, situated near the periphery of the ovary. _Ovulation._—About once a month a general congestion of the entire genital system takes place.[F] This congestion causes an effusion of serum and blood into the Graafian follicle and the rupture of the same. In this way the ovum is set free and is seized by the fimbriae of the Fallopian tube. The ovum begins now its journey towards the uterus. During its progress through the oviduct the maturition of the ovum, or the reduction of its chromosomes to half the number peculiar to its species, takes place by a double segmentation. The ovum is divided, twice in succession, each time into two quite unequal parts. The smaller segments, called polar bodies, remain near the periphery of the ovum and are extruded later on. The ovum is now ripe for fertilization.