A period of exhaustion follows, which is the more intense in proportion to the intensity of the preceding excitement. The sudden fatigue, the general sense of weakness, and the inclination to sleep, which habitually affect the male after the act of intercourse, are in part to be ascribed to the loss of semen; for in the female, however energetic the part she may have played in the sexual act, a mere transient fatigue is observed, much less in degree than that which affects the male, and permitting far sooner of a repetition of the act. “Triste est omne animal post coitum, praeter mulierem gallumque,” wrote Galen, and the axiom is essentially true, at any rate so far as the human species is concerned.
The question has been mooted, and many earnest inquirers have devoted much thought thereto, whether in this moment of most intense sexual gratification it is the male or the female that experiences the greatest amount of pleasure. As in the case of all questions the data for the solution of which are at once very various and very variable, so in this case also, very different opinions have been put forward. “In fact,” writes Roubaud, “when we take into consideration all the circumstances by which the intensity of sexual sensation is influenced, it may well be doubted if it is at all possible to find an a priori solution for the problem. When we take into consideration the influence exercised by temperament, constitution, and a large number of conditions both general and special, on sexual sensibility, we cannot fail to be convinced that this problem, in consequence of all the complicated characteristics it presents, is actually insoluble.”
In regard to the pleasure experienced in the act of intercourse, a remarkable distinction is drawn by Gutceit. The male, in every case and with every woman, experiences the full degree of pleasure; and even though from the mental point of view this pleasure may be enhanced by inclination, attraction, and mutual love, from the physical point of view there is no difference between different acts of intercourse, so that the cynical old Roman was right when he wrote. “Sublata lucerna nullum discrimen inter foeminas.” But in the case of the female it is very different. Her first experience of sexual relations is a very painful one, and this pain prevents all enjoyment as long as it continues, as it does in many women for one, two, or even four weeks. And when this period is once over, not more than two women in every ten experience the pleasure of sexual intercourse in its full intensity. Of the remaining eight, four have indeed an agreeable sensation during the rubbing movements of the sexual act, but it is a long time before they experience a sensation analogous in its intensity to that which in man accompanies the act of ejaculation. In some women it may be six months after marriage before the true sexual orgasm is experienced, in others it may be a year, or even several years; in a considerable number this does not happen until after they have given birth to several children. As a result of numerous observations on this point, Gutceit asserts that in women sexual pleasure is experienced only in intercourse with a man who is beloved, or against whom, at least, no repulsion is felt; and that no pleasure is felt by a woman in intercourse with a man towards whom she feels an actual dislike. Further, he maintains, that a woman, loving another man, and feeling pleasure in intercourse with him, has on the other hand no voluptuous sensations during intercourse with her husband, whose embraces she permits only from a sense of duty. Thus in the male, intercourse is always pleasurable, while in the female, pleasure is experienced only when certain conditions are fulfilled.
Contact with the male genital organs stimulates in the female the sensory nerves of the vulva, the vestibule, and the vagina; the nervous stimulus is transmitted to the cerebral cortex, where it gives rise to the sensation of sexual pleasure, and causes, through the intermediation of the genito-spinal centre, a number of reflex actions. As sensory nerve terminals of such reflex arcs, the final ramifications of the pudic branch of the sciatic plexus play the most important part; in the clitoris these nerves are beset with a peculiar kind of end-bulbs, the genital corpuscles discovered by W. Krause; from their structure these corpuscles seem admirably adapted to respond to the very slightest stimulation, producing voluptuous sensations and perceptions, and giving rise to various reflex manifestations. The first part of the path of the afferent impulses by which sexual pleasure is aroused is constituted by the dorsal nerves of the clitoris. The reflex changes consequent upon sexual excitement begin already in the vestibule, inasmuch as the secretion of Bartholin’s glands, which are compressed by the action of the constrictor cunni muscle, is expelled during coitus, the secretion, owing to the situation of the orifices of Bartholin’s ducts, passing over the external genitals. The clitoris becomes erect; the blood in the bulbs of the vestibule, the venous plexus situated around the margin of the vestibule along the boundary between the labia majora and the labia minora, is pressed into the glans clitoridis, the erection and sensibility of this structure being proportionately heightened. By the action of the constrictor cunni and ischiocavernosus muscles, the clitoris, the distal extremity of which is bent downwards at a right angle, is drawn down and pressed against the penis.
At the entrance of the vagina is the sphincter vaginæ muscle, whose action is reinforced by muscular fibres running in the middle coat of the vagina itself. It is probable that the muscular activity of the vagina and the uterus facilitates the entrance of the semen into the cavity of the uterus.
Dorsal decubitus is rightly regarded as the most correct position, physiologically speaking, for the woman to assume during coitus. That from the earliest times and in the most diverse races, this position has been customary, is shown by numerous antique paintings and statues, and by the reports of those who have studied the customs of savage races. Various other positions are, however, occasionally assumed; thus, Ploss and Bartels report, that among the Soudanese, coitus is practiced in the erect posture, with the man standing behind the woman; that among the Inuits (Eskimo), the act is performed in the manner usual among quadrupeds; that among the Swahelis in Zanzibar, and among the indigens of Kamschatka, the lateral posture is customary; and that among the Australian blacks, coitus is usually effected in the crouching posture, both parties squatting on their hams. The same writers remind us, that in the old calendars of the fifteenth, sixteenth, seventeenth, and eighteenth centuries, definite commands and prohibitions for the conduct of marital intercourse are to be found, and that lucky and unlucky days, respectively, are specified for the performance of the act. These recommendations would appear to be relics of antiquity, for in the Sanscrit work Kokkogam, under the heading “Sexual Intercourse According to the Days of the Month,” exact instructions are given for the proper performance of coitus.
In the Kamasutra (the Indian ars amatoria, a work only in recent days rendered accessible to European readers in the translation of R. Schmidt), several chapters are devoted to the detailed description of the various methods of copulation, and rules are given for the carnal union of man and wife. But, as the Indian author justly remarks, “Rules are of value only for the control of moderate desire; when the wheel of passion has once begun to roll, to prescribe a course is no longer of any avail.” In this work, sixty-four varieties of erotic enjoyment are enumerated, and we find an explicatio coitus secundum mensuram, tempus, naturam, de modis inter coitum procumbendi, de minis coitibus, de coitu inverso, de viri inter coitum consuetudinibus.
At times, in order that coitus may be effective, some other position than the natural one is indispensable. Such a necessity has been recognized even by theologians, by whom any divergence from nature in this matter has usually been regarded as sinful. For instance, in the work of Craisson, De Rebus Venereis ad Usum Confessariorum, we read: “Situs naturalis est ut mulier sit succuba et vir incubus, hic enim modus aptior est effusionis seminis virilis et receptioni in vas femineum ad prolem procreandum. Unde si coitus aliter fiat, nempe sedendo, stando, de latere, vel praepostere (more pecudum), vel si vir sit succubus et mulier incuba, innaturalis est.... Sed tamen minime peccant conjuges si ex justa causa situm mutent, nempe ob aegritudinem, vel viri pinquetudinem, vel ob periculum abortus; quandoque ait St. Thomas, sine peccato esse potest quando dispositio corporis alium modum non patitur.”
In certain pathological states, as for the prevention of sterility, an abnormal posture during coitus may advantageously be recommended, in order to favour the entrance of the semen into the cervical canal, and to allow the semen to stay longer in the vagina before it flows out. An old and often efficacious means for this purpose is the performance of coitus with the woman in the knee-elbow posture. In order to favour the entrance of the semen into the deeper portion of the genital tract, Hegar and Kaltenbach recommend that after coitus the woman should remain for some time in the knee-elbow posture, while the man from time to time gently presses up the anterior abdominal wall, and then abruptly relaxes the pressure.—In the Talmud, coitus was regarded as unfruitful if performed when the woman was in the erect posture.
Casper reports the case of a woman with severe scoliosis, who had long remained sterile, and who only conceived (and was subsequently happily delivered) after performing coitus in the abdominal decubitus.