Читать книгу The Sexual Life of Our Time in Its Relations to Modern Civilization - Iwan 1872-1922 Bloch - Страница 16

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As the progressive evolution of the multicellular organism continued, and there occurred an increasing differentiation of the individual portions of the body, it became necessary that the very simple process of reproduction of the unicellular organism (by simple cell-division or by conjugation) should, in the multicellular organisms of the metazoa, be ensured and facilitated by the development of new apparatus. This was all the more necessary because, owing to the differentiation of the other organs, the originally independent reproductive elements became more and more dependent upon the parent organism, and lost their former capacity for obtaining nourishment by means of their own activity. Hence it became necessary that the period of time elapsing between the moment when the reproductive cells were freed from the parent organism and the moment in which they coalesced to form a new individual should be shortened to a minimum. This purpose is subserved by apparatus which renders possible the secure and rapid coalescence of the two reproductive elements, having the form of special excretory canals with contractile walls, through which the two sexual elements pass. These are the “copulatory organs,” by means of which the distance between the two loving individuals is abridged. According to the exhaustive investigations of Ferdinand Simon, the perfection and differentiation of these conducting canals proceeds pari passu with the higher development of the organism.

Simultaneously therewith proceeds the differentiation of the proper internal reproductive organs, the rudiments of which are identical in the two sexes. A portion of these primitively identical structures undergoes further development in the male, another portion undergoes further development in the female, whilst in both sexes rudiments of the earlier condition are retained, and these bear witness to the primitive state in which both reproductive glands were present in a single individual (hermaphroditism). In this sense Weininger’s theory applies—viz., that there is no absolutely male and no absolutely female individual, that in every man there is something of woman, and in every woman something of man, and that between the two various transitional forms, sexual “intermediate stages,” exist. Therefore, according to this view, every individual has in his composition so many fractions “man” and so many fractions “woman,” and according to the preponderance of one set of elements or the other, he must be assigned to one or the other sex. This theory, which Weininger regards as his own discovery, is by no means new, and already finds a place in Heinse’s “Ardinghello,” where we read:

“I find it therefore necessary to assume the existence in Nature of masculine and feminine elements. That man is nearest perfection who is composed entirely of masculine elements, and that woman perhaps is nearest perfection who contains only so many feminine elements as to be able to remain woman; whilst that man is the worst who contains only so many masculine elements as to qualify for the title of man.”

Magnus Hirschfeld, to whom this noteworthy passage in Heinse’s book appears to be unknown, has recently, in his valuable monographs, “Sexual Stages of Transition” (Leipzig, 1905) and “The Nature of Love” (Leipzig, 1906), thoroughly investigated these relations, and quotes, among others, sayings of Darwin and Weismann, according to which the latent presence of opposite sexual characters in every sexually differentiated bion must be regarded as a normal arrangement. Unquestionably the widely diffused phenomenon of “psychical hermaphroditism,” or “spiritual bisexuality,” is connected with the physical facts just enumerated, and provides us with the key for the understanding of the nature of homosexuality. Both these states—the physical and the mental—may be referred to primitive conditions of sexuality. They cannot play any serious part in the future course of human evolution, of which the progressive differentiation of the sexes is so marked a characteristic. In contrast with this differentiation, these rudimentary sexual conditions are practically devoid of significance. Suggestion, indeed, the influence of momentary tendencies of the time and of transient mental states, may temporarily deceive us. And when, for example, Hirschfeld maintains that in the central nervous system of women the more masculine, rational qualities, and in the central nervous system of men the more feminine, emotional qualities, are respectively on the increase, we must answer, in the first place, that this is not generally true, and, in the second place, that, in so far as it is true, it is a passing phenomenon, which has already provoked a powerful reaction in the opposite direction.[13] The exuviæ of a dead condition cannot again be vitalized.

The original purpose of the organs of sexual congress is, then, to safeguard and to facilitate, in the more complicated conditions peculiar to multicellular organisms, the conjugation of the two reproductive cells. They do not exist, as Eduard von Hartmann assumes, as a mere lure to voluptuousness, to induce man to continue the practice of sexual congress, purely instinctive in his animal ancestors, but now endangered by the development of the higher type of consciousness. For animals without organs of sexual congress also experience a voluptuous sensation at the instant of the sexual orgasm and of procreation.

The history of evolution alone solves the riddle of the origin of the organs of sexual congress, and renders their purpose clear to us. In a most ingenious manner, W. Bölsche distinguishes three problems in this history of the genital organs: the “aperture-problem,” the “member-problem,” and the “libido-problem.”

The first problem relates to the character and the position of the two apertures from which the sexual products, the reproductive cells, issue; the second relates to the exact mutual adaptation of the male and the female reproductive apertures; the third relates to the impulse to the intimate apposition of the genital apertures in consequence of a powerful nervous stimulus.

The most remarkable fact that we encounter in our consideration of the first problem—the “aperture-problem”—is the intimate association between the sexual aperture and the excretory canal of the urinary apparatus both in woman and in man—in the latter, indeed, the association is more pronounced. There seems to be a sort of parsimony on the part of Nature to combine so closely these two excretory tubes of the urine and of the products of sexual activity. Phylogenetically, indeed, the reproductive products originally passed with the urine freely into the open, and it was there that their conjugation took place. Among certain worms still existing at the present day we find this “urine-love.” Later, the genital canal became separated from the urinary canal, but the two tubes remained partly united at their outlets, opening side by side at the same part of the body. In man, indeed, the urethra still subserves the double purpose of the excretion of urine and the emission of semen. In woman the two excretory apertures are distinct, but they open in close proximity into the genital fissure between the thighs.

The intimate connexion which thus obtains between the urinary and the reproductive organs is not without significance for the understanding of certain aberrations of the libido sexualis. The same is true of the relations between the orifice of the genital passage and the similarly adjacent aperture of the large intestine, the anus. “Anus,” or, better, “cloaca love,” plays a part, indeed, in many fishes, amphibia, and reptiles; in these the act of procreation and the excretion of urine and fæces all take place by way of the cloaca. Among the mammals, at an early stage of phylogenetic development the intestine became completely separated from the sexual rudiment and the sexual excretory passages; and it is only in the proximity of the respective orifices that we find an indication of the primitive association. The act of pæderasty reminds us of the same fact.

The “aperture-problem” itself leads us, in the course of progressive development, to the “member-problem”—that is to say, to the problem of the more accurate apposition of the two reproductive apertures. The penis, by its introduction into the body of a member of the opposite sex, acts as a means for the shortening of distance-love; it serves for the fixation, for the clamping together, of the copulating pair, which in earlier stages of animal life was effected by sucking and biting; for example, in birds, who for the most part lack an actual penis, the cock holds the hen firmly with his beak during intercourse, and the sucking and biting which often occur in human beings in the sexual act persist as a reminiscence of these relations. In various vertebrates other means of fixation are employed: by the shape of fins, of arms, or of legs, a close “embrace” is rendered possible; finally, the evolution of a special member for sexual purposes closed the long series of means of ensuring union. Originally no more than a peg or a spine, in man the penis is first developed into the form of an absolutely free limb. Dogs, beasts of prey, rodents, bats, and apes, have a strong bone in the organ, the so-called “penis-bone.” In man this bone is lacking; the penis has become entirely free. W. Bölsche writes:

“In relation to the large, heavy, massive trunk and thighs, the sharply individualized, independent, mobile penis appears as a kind of spiritualized central point; as it were, a finger or a small third hand to the trunk, appearing to the eye to stand in rhythmical relation with the hands, right and left.”

In phylogenetic parallelism with the development of the penis, proceeds (from the marsupials upwards) the descensus testiculorum, the descent of the male reproductive glands, the testicles, until they attain their final position in the scrotum, beneath the penis. Here also we can recognize the principle of “limb-mobility,” mentally refined mobility.

In the clitoris woman also possesses a rudiment of a primitive penis. By the apposition of the two limbs, a more complete and rapid conjunction of the reciprocal sexual products must have been effected. But the further development of the large sexual aperture of the female checked the progressive development of this primitive penis, made it to some extent superfluous, since now, by the adaptation of the male penis to the female sexual aperture, a sufficient internal fixation in the act of copulation was rendered possible. Thus the female penis came to subserve other purposes: a portion of it formed the labia minora; another portion, the upper, the clitoris, the name of which sufficiently indicates the fact that, like the penis of the male, its function is connected with the voluptuous sense.

This leads us to the third and last problem, the “libido-problem.” In the human species voluptuous pleasure is almost completely divorced from the process of “fusion-love,” the coalescence of spermatozoon and ovum, and has for the most part become a phenomenon of “distance-love.” It appears extremely doubtful if there is anything specific about the voluptuous sensation—whether there is, in fact, a special “sexual sense.” Magnus Hirschfeld assumes the existence of peculiar “sexual cells,” of receptive areas for sexual stimuli, furnished with a sensory substance endowed with a peculiar specific sensibility. He regards love and the sexual impulse as “a molecular movement or force of a quite specific quality, streaming through the nervous system,” and accompanied by a quite peculiar sensation, or pleasure-tone, arising from a condition of excitement of the sexual cells. But, as we have already pointed out, the voluptuous sensation is merely a special case of general cutaneous sensibility; it is very closely allied with the cutaneous sensation of tickling; properly speaking, it is no more than an excessively powerful tickling.[14] It has also intimate relations with the sensation of pain.[15] The structure and position of the nerve-terminal apparatus of the genital organs, by means of which voluptuous pleasure is rendered possible, exhibit great similarity with the touch corpuscles and sensory end-organs of other parts of the skin. In the sexual orgasm the general cutaneous sensation increases to so high a degree of intensity, becomes so powerful, that for an instant consciousness is actually lost. The association of a momentary loss of consciousness with the acme of sensation indicates the summit of sexual pleasure—it is an abandonment, a dissolution, of individual personality.

Voluptuous pleasure plays its part in the human species entirely in the sphere of distance-love. Bölsche has very beautifully described its significance in this relation:

“All-embracing in its path towards the attainment of its final aim is the love-life also of the great cell societies, such as you yourself are, such as I myself am, such as your beloved is. These higher, more advanced individuals saw one another, approached one another, heard one another, perceived one another through a hundred external media; they became spiritually fused, and attained a condition of wonderful harmony—their principal body walls came at length into immediate contact—they pressed one another’s hands, they embraced one another, kissed one another—they drew ever closer and closer together; to a certain extent the body of one penetrated the body of the other. In all this, their love undertook the whole affair, undertook it a thousand times more effectually than the individual cells seeking conjunction could ever have done; undertook it for the sake of the reproductive cells hidden deep within their bodies. All the pleasurable and painful feelings of love undulated and surged for so long a time throughout the entire organism with intense force; these feelings agitated the entire superior, comprehensive, individual personality, searched its every depth with stormy emotions of desire, complaint, and exultation.

“But at a precise instant this all came to a halt. The seminal cells were ejaculated; one of them conjugated with the ovum; the hidden inward life of a tiny separate organism began within the body of one of the over-individuals. The last separation was bridged, and the true cell-fusion took place. But when this happened, the immediate relationship with the love-life of the great individual man and woman was already completely severed. The bodily act of love was already long at an end; its increase to a climax and its fulfilment had long passed by.

“The instant of supreme voluptuous pleasure, which in the case of unicellular beings naturally occurs at the moment of complete coalescence, must in the case of the multicellular organisms just as naturally be transferred to another stage, as it were, in the great path of love.

“To an earlier stage.

“To that stage of distance-love which is nearest to the true act of fusion of the reproductive elements. To the farthest point, that is to say, attained by the great containers of the genuine unicellular sexual elements (themselves capable of the act of ultimate coalescence)—the farthest point attained by the multicellular over-individuals.”

This farthest point is an act of contact.[16] We have already learnt to regard the skin as a projection of the nervous system, and we have come to understand the significance of the skin in the sphere of sexuality. The other senses which have arisen from the skin must also be taken into account in this matter. In the genital organs, this touch stimulus assumes a quite peculiar character; it gives rise here to the proper voluptuous sensation which is associated with the discharge of the reproductive products. In man this association is most distinctly manifest. The instant of most intense sexual pleasure coincides with ejaculation, with the expulsion of the semen. The character of this voluptuous sensation can hardly be defined; in part, it is like an intense tickling sensation, but, on the other hand, it has an unmistakable relationship to pain. Later, in another connexion, we shall consider this interesting point at greater length. Not inaptly the sexual act has also been compared with sneezing; the preliminary tickling sensation, with the subsequent discharge of nervous tension, in the form of a sneeze, have, in fact, a notable similarity with the processes occurring in the sexual act.

The sexual act depends upon the occurrence of certain stimuli which are connected with the complete development of the internal and external genital organs and of the reproductive glands. The time when this development occurs in man and woman is known as puberty. The sum of these stimuli is known as the “sexual impulse.” Whereas in the lower animals the sexual impulse is for the most part connected with the activity of the reproductive glands, in the human species, in association with the preponderating significance of the brain, it has attained a relative independence of the reproductive glands; whilst the mind has come to influence the sexual impulse very powerfully. Generally speaking, sexual excitement is produced in three ways: first, by the activity of the reproductive glands; secondly, by peripheral excitement derived from the so-called “erogenic” areas; and thirdly, by central psychical influences. S. Freud has recently studied the relations between these three causes of sexual excitement, of the sexual impulse, and has very properly distinguished two stages—the stage of “prelibido” (sexual desire), and the stage of the proper sexual “libido” (sexual gratification).

The stage of prelibido has distinctly the character of tension; the stage of libido, the character of relief. The feeling of tension during the prelibido finds expression mentally as well as physically by a series of changes in the genital organs. The tension is further increased by the stimulation of the various erogenic zones. If this prelibido increases beyond a certain degree, the characteristic potential energy of sexual tension is transformed into the relief-giving kinetic energy of the terminal libido, during which the evacuation of the reproductive products occurs.

Prelibido, which is especially characterized by engorgement, swelling, and erection of the corpora cavernosa of the male and female reproductive organs, occurring as a reflex from the spinal cord, may be experienced long before puberty; it is much more independent of processes occurring in the reproductive glands than is the terminal libido, or sexual gratification, which in the male accompanies ejaculation of the semen, and is associated with conditions attained only at puberty.

The actual origin of the sexual tension which ultimately leads to ejaculation is still obscure; it seems, at first sight, probable that in the male this sensation is connected with the accumulation of semen in the seminal vesicles. Pressure on the walls of these structures may be supposed to stimulate the sexual centres in the spinal cord, and also those in the brain; but this theory fails to take into account the condition in the child, in woman, and in castrated males, in all of whom, notwithstanding the absence of the accumulation of any reproductive products, nevertheless a distinct state of sexual tension may be observed. It is, indeed, an old experience that eunuchs may have a very powerful sexual impulse. It is obvious, then, that the sexual impulse must be, to a very great extent, independent of the reproductive glands.

The nature of sexual tension is still entirely unknown. Freud assumes, in view of the recently recognized significance of the thyroid glands in relation to sexuality, that possibly some substance generally diffused throughout the organism is produced by stimulation of the erogenic zones, that the products of decomposition of this substance exercise a specific stimulus on the reproductive organs, or on the associated sexual centre in the spinal cord. For example, such a transformation of a toxic, chemical stimulus into a special organ-stimulus is known to occur in the case of certain foreign poisonous materials introduced into the body. Freud considers that the probability of this chemical theory of sexual excitement is increased by the fact that the neuroses referable to disturbances of the sexual life possess a great clinical similarity to the phenomena of intoxication induced by the habitual employment of aphrodisiac poisons (certain alkaloids).

The relief of sexual tension occurs in the natural way in the sexual act, in the completion of normal intercourse between man and woman. Notwithstanding the numerous observations of leading natural philosophers and physicians concerning the act of sexual congress, among which I need only refer to those of Magendie, Johannes Müller, Marshall Hall, Kobelt, Busch, Deslandes, Roubaud, Landois, Theopold, Burdach, and many others, we possess, for reasons it is easy to understand, no really exact investigations regarding the different phenomena occurring during the sexual act. More particularly, the demeanour of the woman during this act is a matter which remains extremely obscure.

The French physician Roubaud has given us the most vivid description of sexual intercourse:

“As soon as the penis enters the vaginal vestibule, it first of all pushes against the glans clitoridis, which is situated at the entrance of the genital canal, and owing to its length and to the way in which it is bent, can give way and bend further before the penis. After this preliminary stimulation of the two chief centres of sexual sensibility, the glans penis glides over the inner surfaces of the two vaginal bulbs; the collum and the body of the penis are then grasped between the projecting surfaces of the vaginal bulbs, but the glans penis itself, which has passed further onward, is in contact with the fine and delicate surface of the vaginal mucous membrane, which membrane itself, owing to the presence of erectile tissue between the layers, is now in an elastic, resilient condition. This elasticity, which enables the vagina to adapt itself to the size of the penis, increases at once the turgescence and the sensibility of the clitoris, inasmuch as the blood that is driven out of the vessels of the vaginal wall passes thence to those of the vaginal bulbs and the clitoris. On the other hand, the turgescence and the sensitiveness of the glans penis itself are heightened by compression of that organ, in consequence of the ever-increasing fulness of the vessels of the vaginal mucous membrane and the two vaginal bulbs.

“At the same time, the clitoris is pressed downwards by the anterior portion of the compressor muscle, so that it is brought into contact with the dorsal surface of the glans and of the body of the penis. In this way a reciprocal friction between these two organs takes place, repeated at each copulatory movement made by the two parties to the act, until at length the voluptuous sensation rises to its highest intensity, and culminates in the sexual orgasm, marked in the male by the ejaculation of the seminal fluid, and in the female by the aspiration of that fluid into the gaping external orifice of the cervical canal.

“When we take into consideration the influence which temperament, constitution, and a number of other special and general circumstances are capable of exercising on the intensity of sexual sensation, it may well be doubted if the problem regarding the differences in voluptuous sensation between the male and the female is anywhere near solution; indeed, we may go further, and feel convinced that this problem, in view of all the difficulties that surround it, is really insoluble. So true is this, that it is a difficult matter to give a picture at once accurate and complete of the phenomena attending the normal act of copulation. Whilst in one individual the sense of sexual pleasure amounts to no more than a barely perceptible titillation, in another that sense reaches the acme of both mental and physical exaltation.

“Between these two extremes we meet with innumerable states of transition. In cases of intense exaltation various pathological symptoms make themselves manifest, such as quickening of the general circulation and violent pulsation of the arteries; the venous blood, being retained in the larger vessels by general muscular contractions, leads to an increased warmth of the body; and, further, this venous stagnation, which is still more marked in the brain in consequence of the contraction of the cervical muscles and the backward flexion of the neck, may cause cerebral congestion, during which consciousness and all mental manifestations are momentarily in abeyance. The eyes, reddened by injection of the conjunctiva, become fixed, and the expression becomes vacant; the lids close convulsively, to exclude the light. In some the breathing becomes panting and labouring; but in others it is temporarily suspended, in consequence of laryngeal spasm, and the air, after being pent up for a time in the lungs, is finally forcibly expelled, accompanied by the utterance of incoherent and incomprehensible words.

“The impulses proceeding from the congested nerve centres are confused. There is an indescribable disorder both of motion and of sensation; the extremities are affected with convulsive twitchings, and may be either moved in various directions or extended straight and stiff; the jaws are pressed together so that the teeth grind against each other; and certain individuals are affected by erotic delirium to such an extent that they will seize the unguarded shoulder, for instance, of their partner in the sexual act, and bite it till the blood flows.

“This delirious frenzy is usually of short duration, but sufficiently long to exhaust the forces of the organism, especially in the male, in whom the condition of hyperexcitability is terminated by a more or less abundant loss of semen.

“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, præter mulierem gallumque,’ wrote Galen, and the axiom is essentially true—at any rate, so far as the human species is concerned.”

Kobelt, in his celebrated work on the human organs of sexual pleasure (Freiburg, 1884, p. 55 et seq.), gave a similar description of copulation. In the majority of descriptions of coitus but little attention is usually paid to the demeanour of the woman. Magendie long ago drew attention to the fact that there was much obscurity about this matter, and insisted that, in comparison with the male, the female exhibited extremely marked differences, in respect to her active participation in copulation and to the intensity of her voluptuous sensations.

“Very many women,” says this distinguished physiologist, “experience a sexual orgasm accompanied by very intense voluptuous sensations; others, on the contrary, appear entirely devoid of sensation; and some, again, have only a disagreeable and painful sensation. Many women excrete, at this moment of most intense sexual pleasure, a large quantity of mucus, but the majority do not exhibit this phenomenon. In reference to all these phenomena, there are perhaps no two women who are precisely similar.”

The demeanour of the woman in coitu has been especially studied by gynæcologists, such as Busch, Theopold, and recently Otto Adler. Little known are the observations of Dr. Theopold, based upon his own experience, and published in 1873. He energetically denies the view that the woman is always passive in coitus, and also that the female reproductive organs are inactive during intercourse. During erotic excitement in woman the heart beats more frequently, the arteries of the labia pulsate powerfully, the genital organs are turgid and are hotter to the touch. As the most intense libido approaches, the uterus undergoes erection; its base touches the anterior abdominal wall; the Fallopian tubes can be distinctly felt through the abdominal wall, when these are thin, as hard, curved strings. The vagina, especially the upper part of the passage, undergoes rhythmical contraction and dilation, and complete gratification terminates the act.

As long as the muscle guarding the vaginal outlet (constrictor cunni—bulbo-cavernosus muscle) is intact, the woman is able, by tightly grasping the root of the penis, to expedite the ejaculation of semen, or to increase the stimulation of the male until ejaculation occurs.

These powerful contractions of the vagina, alternating rhythmically with the dilatations occurring during the orgasm, grip the glans penis tightly, and induce a coaptation of the male urethral orifice with the os uteri externum, and the enlargement of the latter orifice facilitates the entrance of the semen. According to O. Adler, sexual excitement of the woman during sexual intercourse begins with very powerful congestion of the entire reproductive apparatus, including even the fimbriæ surrounding the abdominal orifice of the Fallopian tubes; this congestion gives rise to an erection of these parts, and especially of the clitoris, the labia minora, and the vaginal wall. At the same time, the glands of the vaginal mucous membrane and of the vaginal inlet begin to secrete, as is manifest by the moistness of the external genital organs. There now begin gentle rhythmical contractions of the vagina and of the pelvic muscles, and during the orgasm these increase, to become spasmodic contractions, whereby an increased secretion is extruded, and more especially is there an evacuation of uterine mucus.

It is very important to note the various physiological accompaniments of coitus, since they assist us to understand the mode of origin and the biological root of many sexual perversions. Already in normal sexual intercourse sadistic and masochistic phenomena may be observed. The biting and crying out mentioned by Roubaud as occurring in the voluptuous ecstasy are, indeed, of very frequent occurrence. Rudolf Bergh, the celebrated Danish dermatologist and physician, of the Copenhagen Hospital for Women suffering from Venereal Diseases, alludes regularly in his annual reports to the consequences of “erotic bites.” Amongst the Southern Slavs, the custom of “biting one another” is very general (Krauss). The intense dark red coloration of the face and of the reproductive organs and their environment is also a physiological accompaniment of sexual excitement, and this coloration is more marked in consequence of the associated turgescence of the male and female genital organs; it leads, moreover, to associations of feeling in which the blood plays a dominant part. Hence we deduce the biological and ethnological significance of the colour red in the sphere of sexuality. The nature of the sadist “to see red” during sexual intercourse is, therefore, firmly founded upon a physiological basis, and merely exhibits an increase of a normal phenomenon.[17] The crying and cursing in which many individuals find sexual gratification has also a physiological representative in the inarticulate noises and cries frequently expressed in normal intercourse. It is remarkable that an Indian writer on erotics—Vātsyāyana—deduces this verbal sadism from the various noises which are commonly made in normal intercourse. Similarly, in both parties to the sexual act the presence of masochistic elements can be detected: witness the patience with which pain is borne when it has a voluptuous tinge.[18]

Passing to the consideration of the posture adopted during intercourse, we find in civilized man, who in this respect is far removed from animals, the normal position during coitus is front to front, the woman lying on her back with her lower extremities widely separated, and the knee and hip joints semiflexed; the man lies on her, with his thighs between hers, supporting himself on hands or elbows—or often the two unite their lips in a kiss.

Of all other numerous positions during coitus, or figuræ Veneris, some of which, according to Sheikh Nefzawi, are possible only “in words and thoughts,” the postures that demand consideration on hygienic grounds are, lateral decubitus of the woman, dorsal decubitus of the man, and coitus a posteriori (for example, when man and woman are extremely obese); but this subject belongs rather to the chapter on sexual hygiene.

Ploss-Bartels has proved that the position described above as normal was usual already in ancient times and amongst the most diverse peoples. The adoption of this position in coitus undoubtedly ensued in the human race upon the evolution of the upright posture. It is the natural, instinctive position of civilized man, who in this respect also manifests an advance on the lower animals.