The independence of the sexual impulse from the distention of the sexual glands is further indicated by the great frequency with which sexual sensations, in a faint or even strong degree, are experienced in childhood and sometimes in infancy, and by the fact that they often persist in women long after the sexual glands have ceased their functions.
In the study of auto-erotism in another volume of theseStudiesI have brought together some of the evidence showing that even in very young children spontaneous self-induced sexual excitement, with orgasm, may occur. Indeed, from an early age sexual differences pervade the whole nervous tissue. I may here quote the remarks of an experienced gynecologist: "I venture to think," Braxton Hicks said many years ago, "that those who have much attended to children will agree with me in saying that, almost from the cradle, a difference can be seen in manner, habits of mind, and in illness, requiring variations in their treatment. The change is certainly hastened and intensified at the time of puberty; but there is, even to an average observer, a clear difference between the sexes from early infancy, gradually becoming more marked up to puberty. That sexual feelings exist [it would be better to say 'may exist'] from earliest infancy is well known, and therefore this function does not depend upon puberty, though intensified by it. Hence, may we not conclude that the progress toward development is not so abrupt as has been generally supposed?... The changes of puberty are all of them dependent on the primordial force which, gradually gathering in power, culminates in the perfection both of form and of the sexual system, primary and secondary."There appear to have been but few systematic observations on the persistence of the sexual impulse in women after the menopause. It is regarded as a fairly frequent phenomenon by Kisch, and also by Löwenfeld (Sexualleben und Nervenleiden, p. 29). In America, Bloom (as quoted inMedical Standard, 1896), from an investigation of four hundred cases, found that in some cases the sexual impulse persisted to a very advanced age, and mentions a case of a woman of 70, twenty years past the menopause, who had been long a widow, but had recently married, and who declared that both desire and gratification were as great, if not greater, than before the menopause.
In the study of auto-erotism in another volume of theseStudiesI have brought together some of the evidence showing that even in very young children spontaneous self-induced sexual excitement, with orgasm, may occur. Indeed, from an early age sexual differences pervade the whole nervous tissue. I may here quote the remarks of an experienced gynecologist: "I venture to think," Braxton Hicks said many years ago, "that those who have much attended to children will agree with me in saying that, almost from the cradle, a difference can be seen in manner, habits of mind, and in illness, requiring variations in their treatment. The change is certainly hastened and intensified at the time of puberty; but there is, even to an average observer, a clear difference between the sexes from early infancy, gradually becoming more marked up to puberty. That sexual feelings exist [it would be better to say 'may exist'] from earliest infancy is well known, and therefore this function does not depend upon puberty, though intensified by it. Hence, may we not conclude that the progress toward development is not so abrupt as has been generally supposed?... The changes of puberty are all of them dependent on the primordial force which, gradually gathering in power, culminates in the perfection both of form and of the sexual system, primary and secondary."
There appear to have been but few systematic observations on the persistence of the sexual impulse in women after the menopause. It is regarded as a fairly frequent phenomenon by Kisch, and also by Löwenfeld (Sexualleben und Nervenleiden, p. 29). In America, Bloom (as quoted inMedical Standard, 1896), from an investigation of four hundred cases, found that in some cases the sexual impulse persisted to a very advanced age, and mentions a case of a woman of 70, twenty years past the menopause, who had been long a widow, but had recently married, and who declared that both desire and gratification were as great, if not greater, than before the menopause.
Reference may finally be made to those cases in which the sexual impulse has developed notwithstanding the absence, verified or probable, of any sexual glands at all. In such cases sexual desire and sexual gratification are sometimes even strongerthan normal. Colman has reported a case in which neither ovaries nor uterus could be detected, and the vagina was too small for coitus, but pleasurable intercourse took place by the rectum and sexual desire was at times so strong as to amount almost to nymphomania. Clara Barrus has reported the case of a woman in whom there was congenital absence of uterus and ovaries, as proved subsequently by autopsy, but the sexual impulse was very strong and she had had illicit intercourse with a lover. She suffered from recurrent mania, and then masturbated shamelessly; when sane she was attractively feminine. Macnaughton-Jones describes the case of a woman of 32 with normal sexual feelings and fully developed breasts, clitoris, and labia, but no vagina or internal genitalia could be detected even under the most thorough examination. In a case of Bridgman's, again, the womb and ovaries were absent, and the vagina small, but coitus was not painful, and the voluptuous sensations were complete and sexual passion was strong. In a case of Cotterill's, the ovaries and uterus were of minute size and functionless, and the vagina was absent, but the sexual feelings were normal, and the clitoris preserved its usual sensibility. Mundé had recorded two similar cases, of which he presents photographs. In all these cases not only was the sexual impulse present in full degree, but the subjects were feminine in disposition and of normal womanly conformation; in most cases the external sexual organs were properly developed.[15]
Féré (L'Instinct sexuel, p. 241) has sought to explain away some of these phenomena, in so far as they may be brought against the theory that the secretions and excretions of the sexual glands are the sole source of the sexual impulse. The persistence of sexual feelings after castration may be due, he argues, to the presence of the nerves in the cicatrices, just as the amputated have the illusion that the missing limb is still there. Exactly the same explanation has since been put forward by Moll,Medizinische Klinik, 1905, Nrs. 12 and 13. In the same way the presence of sexual feelings after the menopause may be due to similar irritation determined by degeneration during involution of the glands. The precocious appearance of the sexual impulse in childhood he would explain as due to an anomaly of development in the sexual organs. Féré makes no attempt to explain the presence of thesexual impulse in the congenital absence of the sexual glands; here, however, Mundé intervenes with the suggestion that it is possible that in most cases "an infinitesimal trace of ovary" may exist, and preserve femininity, though insufficient to produce ovulation or menstruation.It is proper to mention these ingenious arguments. They are, however, purely hypothetical, obviously invented to support a theory. It can scarcely be said that they carry conviction. We may rather agree with Guinard that so great is the importance of reproduction that nature has multiplied the means by which preparation is made for the conjunction of the sexes and the roads by which sexual excitation may arrive. As Hirschfeld puts it, in a discussion of this subject (Sexual-Probleme, Feb., 1912), "Nature has several irons in the fire."It will be seen that the conclusions we have reached indirectly involve the assumption that the spinal nervous centers, through which the sexual mechanism operates, are not sufficient to account for the whole of the phenomena of the sexual impulse. The nervous circuit tends to involve a cerebral element, which may sometimes be of dominant importance. Various investigators, from the time of Gall onward, have attempted to localize the sexual instinct centrally. Such attempts, however, cannot be said to have succeeded, although they tend to show that there is a real connection between the brain and the generative organs. Thus Ceni, of Modena, by experiments on chickens, claims to have proved the influence of the cortical centers of procreation on the faculty of generation, for he found that lesions of the cortex led to sterility corresponding in degree to the lesion; but as these results followed even independently of any disturbance of the sexual instinct, their significance is not altogether clear (Carlo Ceni, "L'Influenza dei Centri Corticali sui Fenomeni della Generazione,"Revista Sperimentale di Freniatria, 1907, fasc. 2-3). At present, as Obici and Marchesini have well remarked, all that we can do is to assume the existence of cerebral as well as spinal sexual centers; a cerebral sexual center, in the strictest sense, remains purely hypothetical.Although Gall's attempt to locate the sexual instinct in the cerebellum—well supported as it was by observations—is no longer considered to be tenable, his discussion of the sexual instinct was of great value, far in advance of his time, and accompanied by a mass of facts gathered from many fields. He maintained that the sexual instinct isa function of the brain, not of the sexual organs. He combated the view ruling in his day that the seat of erotic mania must be sought in the sexual organs. He fully dealt with the development of the sexual instinct in many children before maturity of the sexual glands, the prolongation of the instinct into old age, its existence in the castrated and in the congenital absence of the sexual glands; he pointed out that even with an apparently sound and normal sexual apparatus all sorts of psychic pathological deviations may yet occur. In fact, all the lines of argument I have briefly indicated in the foregoing pages—although when they were first written this fact was unknown to me—had been fully discussed by this remarkable man nearly a century ago. (The greater part of the third volume of Gall'sSur les Fonctions du Cerveau, in the edition of 1825, is devoted to this subject. For a good summary, sympathetic, though critical, of Gall's views on this matter, see Möbius, "Ueber Gall's Specielle Organologie,"Schmidt's Jahrbücher der Medicin, 1900, vol. cclxvii; alsoAusgewahlte Werke, vol. vii.)
Féré (L'Instinct sexuel, p. 241) has sought to explain away some of these phenomena, in so far as they may be brought against the theory that the secretions and excretions of the sexual glands are the sole source of the sexual impulse. The persistence of sexual feelings after castration may be due, he argues, to the presence of the nerves in the cicatrices, just as the amputated have the illusion that the missing limb is still there. Exactly the same explanation has since been put forward by Moll,Medizinische Klinik, 1905, Nrs. 12 and 13. In the same way the presence of sexual feelings after the menopause may be due to similar irritation determined by degeneration during involution of the glands. The precocious appearance of the sexual impulse in childhood he would explain as due to an anomaly of development in the sexual organs. Féré makes no attempt to explain the presence of thesexual impulse in the congenital absence of the sexual glands; here, however, Mundé intervenes with the suggestion that it is possible that in most cases "an infinitesimal trace of ovary" may exist, and preserve femininity, though insufficient to produce ovulation or menstruation.
It is proper to mention these ingenious arguments. They are, however, purely hypothetical, obviously invented to support a theory. It can scarcely be said that they carry conviction. We may rather agree with Guinard that so great is the importance of reproduction that nature has multiplied the means by which preparation is made for the conjunction of the sexes and the roads by which sexual excitation may arrive. As Hirschfeld puts it, in a discussion of this subject (Sexual-Probleme, Feb., 1912), "Nature has several irons in the fire."
It will be seen that the conclusions we have reached indirectly involve the assumption that the spinal nervous centers, through which the sexual mechanism operates, are not sufficient to account for the whole of the phenomena of the sexual impulse. The nervous circuit tends to involve a cerebral element, which may sometimes be of dominant importance. Various investigators, from the time of Gall onward, have attempted to localize the sexual instinct centrally. Such attempts, however, cannot be said to have succeeded, although they tend to show that there is a real connection between the brain and the generative organs. Thus Ceni, of Modena, by experiments on chickens, claims to have proved the influence of the cortical centers of procreation on the faculty of generation, for he found that lesions of the cortex led to sterility corresponding in degree to the lesion; but as these results followed even independently of any disturbance of the sexual instinct, their significance is not altogether clear (Carlo Ceni, "L'Influenza dei Centri Corticali sui Fenomeni della Generazione,"Revista Sperimentale di Freniatria, 1907, fasc. 2-3). At present, as Obici and Marchesini have well remarked, all that we can do is to assume the existence of cerebral as well as spinal sexual centers; a cerebral sexual center, in the strictest sense, remains purely hypothetical.
Although Gall's attempt to locate the sexual instinct in the cerebellum—well supported as it was by observations—is no longer considered to be tenable, his discussion of the sexual instinct was of great value, far in advance of his time, and accompanied by a mass of facts gathered from many fields. He maintained that the sexual instinct isa function of the brain, not of the sexual organs. He combated the view ruling in his day that the seat of erotic mania must be sought in the sexual organs. He fully dealt with the development of the sexual instinct in many children before maturity of the sexual glands, the prolongation of the instinct into old age, its existence in the castrated and in the congenital absence of the sexual glands; he pointed out that even with an apparently sound and normal sexual apparatus all sorts of psychic pathological deviations may yet occur. In fact, all the lines of argument I have briefly indicated in the foregoing pages—although when they were first written this fact was unknown to me—had been fully discussed by this remarkable man nearly a century ago. (The greater part of the third volume of Gall'sSur les Fonctions du Cerveau, in the edition of 1825, is devoted to this subject. For a good summary, sympathetic, though critical, of Gall's views on this matter, see Möbius, "Ueber Gall's Specielle Organologie,"Schmidt's Jahrbücher der Medicin, 1900, vol. cclxvii; alsoAusgewahlte Werke, vol. vii.)
It will be seen that the question of the nature of the sexual impulse has been slowly transformed. It is no longer a question of the formation of semen in the male, of the function of menstruation in the female. It has become largely a question of physiological chemistry. The chief parts in the drama of sex, alike on its psychic as on its physical sides, are thus supposed to be played by two mysterious protagonists, the hormones, or internal secretions, of the testes and of the ovary. Even the part played by the brain is now often regarded as chemical, the brain being considered to be a great chemical laboratory. There is a tendency, moreover, to extend the sexual sphere so as to admit the influence of internal secretions from other glands. The thymus, the adrenals, the thyroid, the pituitary, even the kidneys: it is possible that internal secretions from all these glands may combine to fill in the complete picture of sexuality as we know it in men and women.[16]The subject is, however,so complex and at present so little known that it would be hazardous, and for the present purpose it is needless, to attempt to set forth any conclusions.
It is sufficiently clear that there is on the surface a striking analogy between sexual desire and the impulse to evacuate an excretion, and that this analogy is not only seen in the frog, but extends also to the highest vertebrates. It is quite another matter, however, to assert that the sexual impulse can be adequately defined as an impulse to evacuate. To show fully the inadequate nature of this conception would require a detailed consideration of the facts of sexual life. That is, however, unnecessary. It is enough to point out certain considerations which alone suffice to invalidate this view. In the first place, it must be remarked that the trifling amount of fluid emitted in sexual intercourse is altogether out of proportion to the emotions aroused by the act and to its after-effect on the organism; the ancient dictumomne animal post coitum tristemay not be exact, but it is certain that the effect of coitus on the organism is far more profound than that produced by the far more extensive evacuation of the bladder or bowels. Again, this definition leaves unexplained all those elaborate preliminaries which, both in man and the lower animals, precede the sexual act, preliminaries which in civilized human beings sometimes themselves constitute a partial satisfaction to the sexual impulse. It must also be observed that, unlike the ordinary excretions, this discharge of the sexual glands is not always, or in every person, necessary at all. Moreover, the theory of evacuation at once becomes hopelessly inadequate when we apply it to women; no one will venture to claim that an adequate psychological explanation of the sexual impulse in a woman is to be found in the desire to expel a little bland mucus from the minute glands of the genital tract. We must undoubtedly reject this view of the sexual impulse. It has a certain element of truth and it permits an instructive and helpful analogy; but that is all. The sexual act presents many characters which are absent in an ordinary act of evacuation, and, on the other hand, it lacks thespecial characteristic of the evacuation proper, the elimination of waste material; the seminal fluid is not a waste material, and its retention is, to some extent perhaps, rather an advantage than a disadvantage to the organism.
Eduard von Hartmann long since remarked that the satisfaction of what we call the sexual instinct through an act carried out with a person of the opposite sex is a very wonderful phenomenon. It cannot be said, however, that the conception of the sexual act as a simple process of evacuation does anything to explain the wonder. We are, at most, in the same position as regards the stilling of normal sexual desire as we should be as regards the emptying of the bladder, supposing it were very difficult for either sex to effect this satisfactorily without the aid of a portion of the body of a person of the other sex acting as a catheter. In such a case our thoughts and ideals would center around persons of opposite sex, and we should court their attention and help precisely as we do now in the case of our sexual needs. Some such relationship does actually exist in the case of the suckling mother and her infant. The mother is indebted to the child for the pleasurable relief of her distended breasts; and, while in civilization more subtle pleasures and intelligent reflection render this massive physical satisfaction comparatively unessential to the act of suckling, in more primitive conditions and among animals the need of this pleasurable physical satisfaction is a real bond between the mother and her offspring. The analogy is indeed very close: the erectile nipple corresponds to the erectile penis, the eager watery mouth of the infant to the moist and throbbing vagina, the vitally albuminous milk to the vitally albuminous semen.[17]The completemutual satisfaction, physical and psychic, of mother and child, in the transfer from one to the other of a precious organized fluid, is the one true physiological analogy to the relationship of a man and a woman at the climax of the sexual act. Even this close analogy, however, fails to cover all the facts of the sexual life.
A very different view is presented to us in the definition of the sexual instinct as a reproductive impulse, a desire for offspring. Hegar, Eulenburg, Näcke, and Löwenfeld have accepted this as, at all events, a partial definition.[18]No one, indeed, would argue that it is a complete definition, although a few writers appear to have asserted that it is so sometimes as regards the sexual impulse in women. There is, however, considerable mental confusion in the attempt to set up such a definition. If we define an instinct as an action adapted to an end which is not present to consciousness, then it is quite true that the sexual instinct is an instinct of reproduction. But we do not adequately define the sexual instinct by merely stating its ultimate object. We might as well say that the impulse by which young animals seize food is "an instinct of nutrition." The object of reproduction certainly constitutes no part of the sexual impulse whatever in any animal apart from man, and it reveals a lack of the most elementary sense of biological continuity to assert that in man so fundamental and involuntary a process can suddenly be revolutionized. Thatthe sexual impulse is very often associated with a strong desire for offspring there can be no doubt, and in women the longing for a child—that is to say, the longing to fulfill those functions for which their bodies are constituted—may become so urgent and imperative that we may regard it as scarcely less imperative than the sexual impulse. But it is not the sexual impulse, though intimately associated with it, and though it explains it. A reproductive instinct might be found in parthenogenetic animals, but would be meaningless, because useless, in organisms propagating by sexual union. A woman may not want a lover, but may yet want a child. This merely means that her maternal instincts have been aroused, while her sexual instincts are still latent. A desire for reproduction, as soon as that desire becomes instinctive, necessarily takes on the form of the sexual impulse, for there is no other instinctive mechanism by which it can possibly express itself. A "reproductive instinct," apart from the sexual instinct and apart from the maternal instinct, cannot be admitted; it would be an absurdity. Even in women in whom the maternal instincts are strong, it may generally be observed that, although before a woman is in love, and also during the later stages of her love, the conscious desire for a child may be strong, during the time when sexual passion is at its highest the thought of offspring, under normally happy conditions, tends to recede into the background. Reproduction is the natural end and object of the sexual instinct, but the statement that it is part of the contents of the sexual impulse, or can in any way be used to define that impulse, must be dismissed as altogether inacceptable. Indeed, although the term "reproductive instinct" is frequently used, it is seldom used in a sense that we need take seriously; it is vaguely employed as a euphemism by those who wish to veil the facts of the sexual life; it is more precisely employed mainly by those who are unconsciously dominated by a superstitious repugnance to sex.
I now turn to a very much more serious and elaborate attempt to define the constitution of the sexual impulse, that of Moll. He finds that it is made up of two separate components,each of which may be looked upon as an uncontrollable impulse.[19]One of these is that by which the tension of the sexual organs is spasmodically relieved; this he calls theimpulse of detumescence,[20]and he regards it as primary, resembling the impulse to empty a full bladder. The other impulse is the "instinct to approach, touch, and kiss another person, usually of the opposite sex"; this he terms theimpulse of contrectation, and he includes under this head not only the tendency to general physical contact, but also the psychic inclination to become generally interested in a person of the opposite sex. Each of these primary impulses Moll regards as forming a constituent of the sexual instinct in both men and women. It seems to me undoubtedly true that these two impulses do correspond to the essential phenomena. The awkward and unsatisfactory part of Moll's analysis is the relation of the one to the other. It is true that he traces both impulses back to the sexual glands, that of detumescence directly, that of contrectation indirectly; but evidently he does not regard them as intimately related to each other; he insists on the fact that they may exist apart from each other, that they do not appear synchronously in youth: the contrectation impulse he regards as secondary; it is, he states, an indirect result of the sexual glands, "only to be understood by the developmental history of these glands and the object which they subserve"; that is to say, that it is connected with the rise of the sexual method of reproduction and the desirability of the mingling of the two sexes in procreation, while the impulse of detumescence arose before the sexual method of reproduction had appeared; thus the contrectation impulse was propagated by natural selection together with the sexual method of reproduction. The impulse of contrectation is secondary, and Moll even regards it as a secondary sexual character.
While, therefore, this analysis seems to include all the phenomena and to be worthy of very careful study as a seriousand elaborate attempt to present an adequate psychological definition of the sexual impulse, it scarcely seems to me that we can accept it in precisely the form in which Moll presents it. I believe, however, that by analyzing the process a little more minutely we shall find that these two constituents of the sexual impulse are really much more intimately associated than at the first glance appears, and that we need by no means go back to the time when the sexual method of reproduction arose to explain the significance of the phenomena which Moll includes under the term contrectation.
To discover the true significance of the phenomena in men it is necessary to observe carefully the phenomena of love-making not only among men, but among animals, in which the impulse of contrectation plays a very large part, and involves an enormous expenditure of energy. Darwin was the first to present a comprehensive view of, at all events a certain group of, the phenomena of contrectation in animals; on his interpretation of those phenomena he founded his famous theory of sexual selection. We are not primarily concerned with that theory; but the facts on which Darwin based his theory lie at the very roots of our subject, and we are bound to consider their psychological significance. In the first place, since these phenomena are specially associated with Darwin's name, it may not be out of place to ask what Darwin himself considered to be their psychological significance. It is a somewhat important question, even for those who are mainly concerned with the validity of the theory which Darwin established on those facts, but so far as I know it has not hitherto been asked. I find that a careful perusal of theDescent of Manreveals the presence in Darwin's mind of two quite distinct theories, neither of them fully developed, as to the psychological meaning of the facts he was collecting. The two following groups of extracts will serve to show this very conclusively: "The lower animals have a sense of beauty," he declares, "powers of discrimination and taste on the part of the female" (p. 211[21]); "the females habituallyor occasionally prefer the more beautiful males," "there is little improbability in the females of insects appreciating beauty in form or color" (p. 329); he speaks of birds as the most "esthetic" of all animals excepting man, and adds that they have "nearly the same taste for the beautiful as we have" (p. 359); he remarks that a change of any kind in the structure or color of the male bird "appears to have been admired by the female" (p. 385). He speaks of the female Argus pheasant as possessing "this almost human degree of taste." Birds, again, "seem to have some taste for the beautiful both in color and sound," and "we ought not to feel too sure that the female does not attend to each detail of beauty" (p. 421). Novelty, he says, is "admired by birds for its own sake" (p. 495). "Birds have fine powers of discrimination and in some few instances it can be shown that they have a taste for the beautiful" (p. 496). The "esthetic capacity" of female animals has been advanced by exercise just as our own taste has improved (p. 616). On the other hand, we find running throughout the book quite another idea. Of cicadas he tells us that it is probable that, "like female birds, they are excited or allured by the male with the most attractive voice" (p. 282); and, coming toLocustidæ, he states that "all observers agree that the sounds serve either to call or excite the mute females" (p. 283). Of birds he says, "I am led to believe that the females prefer or are most excited by the more brilliant males" (p. 316). Among birds also the males "endeavor to charm or excite their mates by love-notes," etc., and "the females are excited by certain males, and thus unconsciously prefer them" (p. 367), while ornaments of all kinds "apparently serve to excite, attract, or fascinate the female" (p. 394). In a supplemental note, also, written in 1876, five years after the first publication of theDescent of Man, and therefore a late statement of his views, Darwin remarks that "no supporter of the principle of sexual selection believes that the females select particular points of beauty in the males; they are merely excited or attracted in a greater degree by one male than by another, and this seems often to depend, especiallywith birds, on brilliant coloring" (p. 623). Thus, on the one hand, Darwin interprets the phenomena as involving a real esthetic element, a taste for the beautiful; on the other hand, he states, without apparently any clear perception that the two views are quite distinct, that the colors and sounds and other characteristics of the male are not an appeal to any esthetic sense of the female, but an appeal to her sexual emotions, a stimulus to sexual excitement, an allurement to sexual contact. According to the first theory, the female admires beauty, consciously or unconsciously, and selects the most beautiful partner[22]; according to the second theory, there is no esthetic question involved, but the female is unconsciously influenced by the most powerful or complex organic stimulus to which she is subjected. There can be no question that it is the second, and not the first, of these two views which we are justified in accepting. Darwin, it must be remembered, was not a psychologist, and he lived before the methods of comparative psychology had begun to be developed; had he written twenty years later we may be sure he would never have used so incautiously some of the vague and hazardous expressions I have quoted. He certainly injured his theory of sexual selection by stating it in too anthropomorphic language, by insisting on "choice," "preference," "esthetic sense," etc. There is no need whatever to burden any statement of the actual facts by such terms borrowed from human psychology. The female responds to the stimulation of the male at the right moment just as the tree responds to the stimulation of the warmest days in spring. We should but obscure this fact by stating that the tree "chooses" the most beautiful days on which to put forth its young sprouts. In explaining the correlation between responsive females and accomplished males the supposition of estheticchoice is equally unnecessary. It is, however, interesting to observe that, though Darwin failed to see that the love-combats, pursuits, dances, and parades of the males served as a method of stimulating the impulse of contrectation—or, as it would be better to term it, tumescence—in the male himself,[23]he to some extent realized the part thus played in exciting the equally necessary activity of tumescence in the female.
The justification for using the term "tumescence," which I here propose, is to be found in the fact that vascular congestion, more especially of the parts related to generation, is an essential preliminary to acute sexual desire. This is clearly brought out in Heape's careful study of the "sexual season" in mammals. Heape distinguishes between the "pro-estrum," or preliminary period of congestion, in female animals and the immediately following "estrus," or period of desire. The latter period is the result of the former, and, among the lower animals at all events, intercourse only takes place during the estrus, not during the pro-estrum. Tumescence must thus be obtained before desire can become acute, and courtship runspari passuwith physiological processes. "Normal estrus," Heape states, "occurs in conjunction with certain changes in the uterine tissue, and this is accompanied by congestion and stimulation or irritation of the copulatory organs.... Congestion is invariably present and is an essential condition.... The first sign of pro-estrum noticed in the lower mammals is a swollen and congested vulva and a general restlessness, excitement, or uneasiness. There are other signs familiar to breeders of various mammals, such as the congested conjunctiva of the rabbit's eye and the drooping ears of the pig. Many monkeys exhibit congestion of the face and nipples, as well as of the buttocks, thighs, and neighboring parts; sometimes they are congested to a very marked extent, and in some species a swelling, occasionally prodigious, of the soft tissues round the anal and generative openings, which is also at the time brilliantly congested, indicates the progress of the pro-estrum.... The growth of the stroma-tissue [in the uterus of monkeys during the pro-estrum] is rapidly followed by an increase in the number and size of the vessels of the stroma; the whole becomes richly supplied with blood, and the surface is flushed and highly vascular. This process goes on until the whole of the internal stroma becomes tense and brilliantly injectedwith blood.... In all essential points the menstruation or pro-estrum of the human female is identical with that of monkeys.... Estrus is possible only after the changes due to pro-estrum have taken place in the uterus. A wave of disturbance, at first evident in the external generative organs, extends to the uterus, and after the various phases of pro-estrum have been gone through in that organ, and the excitement there is subsiding, it would seem as if the external organs gain renewed stimulus, and it is then that estrus takes place.... In all animals which have been investigated coition is not allowed by the female until some time after the swelling and congestion of the vulva and surrounding tissue are first demonstrated, and in those animals which suffer from a considerable discharge of blood the main portion of that discharge, if not the whole of it, will be evacuated before sexual intercourse is allowed." (W. Heape, "The 'Sexual Season' of Mammals,"Quarterly Journal of Microscopical Science, vol. xliv, Part I, 1900. Estrus has since been fully discussed in Marshall'sPhysiology of Reproduction.) This description clearly brings out the fundamentally vascular character of the process I have termed "tumescence"; it must be added, however, that in man the nervous elements in the process tend to become more conspicuous, and more or less obliterate these primitive limitations of sexual desire. (See "Sexual Periodicity" in the first volume of theseStudies.)Moll subsequently restated his position with reference to my somewhat different analysis of the sexual impulse, still maintaining his original view ("Analyse des Geschlechtstriebes,"Medizinische Klinik, Nos. 12 and 13, 1905; alsoGeschlecht und Gesellschaft, vol. ii, Nos. 9 and 10). Numa Praetorius (Jahrbuch für Sexeuelle Zwischenstufen, 1904, p. 592) accepts contrectation, tumescence, and detumescence as all being stages in the same process, contrectation, which he defines as the sexual craving for a definite individual, coming first. Robert Müller (Sexualbiologie, 1907, p. 37) criticises Moll much in the same sense as I have done and considers that contrectation and detumescence cannot be separated, but are two expressions of the same impulse; so also Max Katte, "Die Präliminarien des Geschlechtsaktes,"Zeitschrift für Sexualwissenschaft, Oct., 1908, and G. Saint-Paul,L'Homosexualité et les Types Homosexuels, 1910, p. 390.While I regard Moll's analysis as a valuable contribution to the elucidation of the sexual impulse, I must repeat that I cannot regard it as final or completely adequate. As I understand the process, contrectation is an incident in the development of tumescence, an extremely important incident indeed, but not an absolutely fundamental and primitive part of it. It is equally an incident, highly important though not primitive and fundamental, of detumescence. Contrectation,from first to last; furnishes the best conditions for the exercise of the sexual process, but it is not an absolutely essential part of the process and in the early stages of zoölogical development it had no existence at all. Tumescence and detumescence are alike fundamental, primitive, and essential; in resting the sexual impulse on these necessarily connected processes we are basing ourselves on the solid bedrock of nature.Moreover, of the two processes, tumescence, which in time comes first, is by far the most important, and nearly the whole of sexual psychology is rooted in it. To assert, with Moll, that the sexual process may be analyzed into contrectation and detumescence alone is to omit the most essential part of the process. It is much the same as to analyze the mechanism of a gun into probable contact with the hand, and a more or less independent discharge, omitting all reference to the loading of the gun. The essential elements are the loading and the discharging. Contrectation is a part of loading, though not a necessary part, since the loading may be effected mechanically. But to understand the process of firing a gun and to comprehend the mechanism of the discharge, we must insist on the act of loading and not merely on the contact of the hand. So it is in analyzing the sexual impulse. Contrectation is indeed highly important, but it is important only in so far as it aids tumescence, and so may be subordinated to tumescence, exactly as it may also be subordinated to detumescence. It is tumescence which is the really essential part of the process, and we cannot afford, with Moll, to ignore it altogether.
The justification for using the term "tumescence," which I here propose, is to be found in the fact that vascular congestion, more especially of the parts related to generation, is an essential preliminary to acute sexual desire. This is clearly brought out in Heape's careful study of the "sexual season" in mammals. Heape distinguishes between the "pro-estrum," or preliminary period of congestion, in female animals and the immediately following "estrus," or period of desire. The latter period is the result of the former, and, among the lower animals at all events, intercourse only takes place during the estrus, not during the pro-estrum. Tumescence must thus be obtained before desire can become acute, and courtship runspari passuwith physiological processes. "Normal estrus," Heape states, "occurs in conjunction with certain changes in the uterine tissue, and this is accompanied by congestion and stimulation or irritation of the copulatory organs.... Congestion is invariably present and is an essential condition.... The first sign of pro-estrum noticed in the lower mammals is a swollen and congested vulva and a general restlessness, excitement, or uneasiness. There are other signs familiar to breeders of various mammals, such as the congested conjunctiva of the rabbit's eye and the drooping ears of the pig. Many monkeys exhibit congestion of the face and nipples, as well as of the buttocks, thighs, and neighboring parts; sometimes they are congested to a very marked extent, and in some species a swelling, occasionally prodigious, of the soft tissues round the anal and generative openings, which is also at the time brilliantly congested, indicates the progress of the pro-estrum.... The growth of the stroma-tissue [in the uterus of monkeys during the pro-estrum] is rapidly followed by an increase in the number and size of the vessels of the stroma; the whole becomes richly supplied with blood, and the surface is flushed and highly vascular. This process goes on until the whole of the internal stroma becomes tense and brilliantly injectedwith blood.... In all essential points the menstruation or pro-estrum of the human female is identical with that of monkeys.... Estrus is possible only after the changes due to pro-estrum have taken place in the uterus. A wave of disturbance, at first evident in the external generative organs, extends to the uterus, and after the various phases of pro-estrum have been gone through in that organ, and the excitement there is subsiding, it would seem as if the external organs gain renewed stimulus, and it is then that estrus takes place.... In all animals which have been investigated coition is not allowed by the female until some time after the swelling and congestion of the vulva and surrounding tissue are first demonstrated, and in those animals which suffer from a considerable discharge of blood the main portion of that discharge, if not the whole of it, will be evacuated before sexual intercourse is allowed." (W. Heape, "The 'Sexual Season' of Mammals,"Quarterly Journal of Microscopical Science, vol. xliv, Part I, 1900. Estrus has since been fully discussed in Marshall'sPhysiology of Reproduction.) This description clearly brings out the fundamentally vascular character of the process I have termed "tumescence"; it must be added, however, that in man the nervous elements in the process tend to become more conspicuous, and more or less obliterate these primitive limitations of sexual desire. (See "Sexual Periodicity" in the first volume of theseStudies.)
Moll subsequently restated his position with reference to my somewhat different analysis of the sexual impulse, still maintaining his original view ("Analyse des Geschlechtstriebes,"Medizinische Klinik, Nos. 12 and 13, 1905; alsoGeschlecht und Gesellschaft, vol. ii, Nos. 9 and 10). Numa Praetorius (Jahrbuch für Sexeuelle Zwischenstufen, 1904, p. 592) accepts contrectation, tumescence, and detumescence as all being stages in the same process, contrectation, which he defines as the sexual craving for a definite individual, coming first. Robert Müller (Sexualbiologie, 1907, p. 37) criticises Moll much in the same sense as I have done and considers that contrectation and detumescence cannot be separated, but are two expressions of the same impulse; so also Max Katte, "Die Präliminarien des Geschlechtsaktes,"Zeitschrift für Sexualwissenschaft, Oct., 1908, and G. Saint-Paul,L'Homosexualité et les Types Homosexuels, 1910, p. 390.
While I regard Moll's analysis as a valuable contribution to the elucidation of the sexual impulse, I must repeat that I cannot regard it as final or completely adequate. As I understand the process, contrectation is an incident in the development of tumescence, an extremely important incident indeed, but not an absolutely fundamental and primitive part of it. It is equally an incident, highly important though not primitive and fundamental, of detumescence. Contrectation,from first to last; furnishes the best conditions for the exercise of the sexual process, but it is not an absolutely essential part of the process and in the early stages of zoölogical development it had no existence at all. Tumescence and detumescence are alike fundamental, primitive, and essential; in resting the sexual impulse on these necessarily connected processes we are basing ourselves on the solid bedrock of nature.
Moreover, of the two processes, tumescence, which in time comes first, is by far the most important, and nearly the whole of sexual psychology is rooted in it. To assert, with Moll, that the sexual process may be analyzed into contrectation and detumescence alone is to omit the most essential part of the process. It is much the same as to analyze the mechanism of a gun into probable contact with the hand, and a more or less independent discharge, omitting all reference to the loading of the gun. The essential elements are the loading and the discharging. Contrectation is a part of loading, though not a necessary part, since the loading may be effected mechanically. But to understand the process of firing a gun and to comprehend the mechanism of the discharge, we must insist on the act of loading and not merely on the contact of the hand. So it is in analyzing the sexual impulse. Contrectation is indeed highly important, but it is important only in so far as it aids tumescence, and so may be subordinated to tumescence, exactly as it may also be subordinated to detumescence. It is tumescence which is the really essential part of the process, and we cannot afford, with Moll, to ignore it altogether.
Wallace opposed Darwin's theory of sexual selection, but it can scarcely be said that his attitude toward it bears critical examination. On the one hand, as has already been noted, he saw but one side of that theory and that the unessential side, and, on the other hand, his own view really coincided with the more essential elements in Darwin's theory. In hisTropical Naturehe admitted that the male's "persistency and energy win the day," and also that this "vigor and liveliness" of the male are usually associated with intense coloration, while twenty years later (in hisDarwinism) he admitted also that it is highly probable that the female is pleased or excited by the male's display. But all that is really essential in Darwin's theory is involved, directly or indirectly, in these admissions.
Espinas, in 1878, in his suggestive book,Des Sociétés Animales, described the odors, colors and forms, sounds, games, parades, and mock battles of animals, approaching the subjectin a somewhat more psychological spirit than either Darwin or Wallace, and he somewhat more clearly apprehended the object of these phenomena in producing mutual excitement and stimulating tumescence. He noted the significance of the action of the hermaphroditic snails in inserting their darts into each other's flesh near the vulva in order to cause preliminary excitation. He remarks of this whole group of phenomena: "It is the preliminary of sexual union, it constitutes the first act of it. By it the image of the male is graven on the consciousness of the female, and in a manner impregnates it, so as to determine there, as the effects of this representation descend to the depths of the organism, the physiological modifications necessary to fecundation." Beaunis, again, in an analysis of the sexual sensations, was inclined to think that the dances and parades of the male are solely intended to excite the female, not perceiving, however, that they at the same time serve to further excite the male also.[24]
A better and more comprehensive statement was reached by Tillier, who, to some extent, may be said to have anticipated Groos. Darwin, Tillier pointed out, had not sufficiently taken into account the coexistence of combat and courtship, nor the order of the phenomena. Courtship without combat, Tillier argued, is rare; "there is a normal coexistence of combat and courtship."[25]Moreover, he proceeded, force is the chief factorin determining the possession of the female by the male, who in some species is even prepared to exert force on her; so that the female has little opportunity of sexual selection, though she is always present at these combats. He then emphasized the significant fact that courtship takes place long after pairing has ceased, and the question of selection thus been eliminated. The object of courtship, he concluded, is not sexual selection by the female, but the sexual excitement of both male and female, such excitement, he asserted, not only rendering coupling easier, but favoring fecundation. Modesty, also, Tillier further argued, again anticipating Groos, works toward the same end; it renders the male more ardent, and by retarding coupling may also increase the secretions of the sexual glands and favor the chances of reproduction.[26]
In a charming volume entitledThe Naturalist in La Plata(1892) Mr. W. H. Hudson included a remarkable chapter on "Music and Dancing in Nature." In this chapter he described many of the dances, songs, and love-antics of birds, but regarded all such phenomena as merely "periodical fits of gladness." While, however, we may quite well agree with Mr. Hudson that conscious sexual gratification on the part of the female is not the cause of music and dancing performances in birds, nor of the brighter colors and ornaments that distinguish the male, such an opinion by no means excludes the conclusion that these phenomena are primarily sexual and intimately connected with the process of tumescence in both sexes. It is noteworthy that, according to H. E. Howard ("On Sexual Selection in Birds,"Zoölogist, Nov., 1903), color is most developed just before pairing, rapidly becoming less beautiful—even within a few hours—after this, and the most beautiful male is most successful in getting paired. The fact that, as Mr. Hudson himself points out, it is at the season of love that these manifestations mainly, if not exclusively, appear, and that it is the more brilliant and highly endowed males which play the chief part in them, only serves to confirm such a conclusion. To argue, with Mr. Hudson, that they cannot be sexual because they sometimes occur before the arrival of the females, is much the same as to argue that theantics of a kitten with a feather or a reel have no relationship whatever to mice. The birds that began earliest to practise their accomplishments would probably have most chance of success when the females arrived. Darwin himself said that nothing is commoner than for animals to take pleasure in practising whatever instinct they follow at other times for some real good. These manifestations are primarily for the sake of producing sexual tumescence, and could not well have been developed to the height they have reached unless they were connected closely with propagation. That they may incidentally serve to express "gladness" one need not feel called upon to question.Another observer of birds, Mr. E. Selous, has made observations which are of interest in this connection. He finds that all bird-dances are not nuptial, but that some birds—the stone-curlew (or great plover), for example—have different kinds of dances. Among these birds he has made the observation, very significant from our present point of view, that the nuptial dances, taken part in by both of the pair, are immediately followed by intercourse. In spring "all such runnings and chasings are, at this time, but a part of the business of pairing, and one divines at once that such attitudes are of a sexual character.... Here we have a bird with distinct nuptial (sexual) and social (non-sexual) forms of display or antics, and the former as well as the latter are equally indulged in by both sexes." (E. Selous,Bird Watching, pp. 15-20.)The same author (ibid., pp. 79, 94) argues that in the fights of two males for one female—with violent emotion on one side and interested curiosity on the other—the attitude of the former "might gradually come to be a display made entirely for the female, and of the latter a greater or less degree of pleasurable excitement raised by it, with a choice in accordance." On this view the interest of the female would first have been directed, not to the plumage, but to the frenzied actions and antics of the male. From these antics in undecorated birds would gradually develop the interest in waving plumes and fluttering wings. Such a dance might come to be of a quite formal and non-courting nature.Last, we owe to Professor Häcker what may fairly be regarded, in all main outlines, as an almost final statement of the matter. In hisGesang der Vögel(1900) he gives a very clear account of the evolution of bird-song, which he regards as the most essential element in all this group of manifestations, furnishing the key also to the dancing and other antics. Originally the song consists only of call-cries and recognition-notes. Under the parallel influence of natural selection and sexual selection they become at the pairing season reflexes of excitement and thus develop into methods of producing excitement, in the male by themuscular energy required, and in the female through the ear; finally they become play, though here also it is probable that use is not excluded. Thus, so far as the male bird is concerned, bird-song possesses a primary prenuptial significance in attracting the female, a secondary nuptial significance in producing excitement (p. 48). He holds also that the less-developed voices of the females aid in attaining the same end (p. 51). Finally, bird-song possesses a tertiary extranuptial significance (including exercise play, expression of gladness). Häcker points out, at the same time, that the maintenance of some degree of sexual excitement beyond pairing time may be of value for the preservation of the species, in case of disturbance during breeding and consequent necessity for commencing breeding over again.Such a theory as this fairly coincides with the views brought forward in the preceding pages,—views which are believed to be in harmony with the general trend of thought today,—since it emphasizes the importance of tumescence and all that favors tumescence in the sexual process. The so-called esthetic element in sexual selection is only indirectly of importance. The male's beauty is really a symbol of his force.It will be seen that this attitude toward the facts of tumescence among birds and other animals includes the recognition of dances, songs, etc., as expressions of "gladness." As such they are closely comparable to the art manifestations among human races. Here, as Weismann in hisGedanken über Musikhas remarked, we may regard the artistic faculty as a by-product: "This [musical] faculty is, as it were, the mental hand with which we play on our own emotional nature, a hand not shaped for this purpose, not due to the necessity for the enjoyment of music, but owing its origin to entirely different requirements."
In a charming volume entitledThe Naturalist in La Plata(1892) Mr. W. H. Hudson included a remarkable chapter on "Music and Dancing in Nature." In this chapter he described many of the dances, songs, and love-antics of birds, but regarded all such phenomena as merely "periodical fits of gladness." While, however, we may quite well agree with Mr. Hudson that conscious sexual gratification on the part of the female is not the cause of music and dancing performances in birds, nor of the brighter colors and ornaments that distinguish the male, such an opinion by no means excludes the conclusion that these phenomena are primarily sexual and intimately connected with the process of tumescence in both sexes. It is noteworthy that, according to H. E. Howard ("On Sexual Selection in Birds,"Zoölogist, Nov., 1903), color is most developed just before pairing, rapidly becoming less beautiful—even within a few hours—after this, and the most beautiful male is most successful in getting paired. The fact that, as Mr. Hudson himself points out, it is at the season of love that these manifestations mainly, if not exclusively, appear, and that it is the more brilliant and highly endowed males which play the chief part in them, only serves to confirm such a conclusion. To argue, with Mr. Hudson, that they cannot be sexual because they sometimes occur before the arrival of the females, is much the same as to argue that theantics of a kitten with a feather or a reel have no relationship whatever to mice. The birds that began earliest to practise their accomplishments would probably have most chance of success when the females arrived. Darwin himself said that nothing is commoner than for animals to take pleasure in practising whatever instinct they follow at other times for some real good. These manifestations are primarily for the sake of producing sexual tumescence, and could not well have been developed to the height they have reached unless they were connected closely with propagation. That they may incidentally serve to express "gladness" one need not feel called upon to question.
Another observer of birds, Mr. E. Selous, has made observations which are of interest in this connection. He finds that all bird-dances are not nuptial, but that some birds—the stone-curlew (or great plover), for example—have different kinds of dances. Among these birds he has made the observation, very significant from our present point of view, that the nuptial dances, taken part in by both of the pair, are immediately followed by intercourse. In spring "all such runnings and chasings are, at this time, but a part of the business of pairing, and one divines at once that such attitudes are of a sexual character.... Here we have a bird with distinct nuptial (sexual) and social (non-sexual) forms of display or antics, and the former as well as the latter are equally indulged in by both sexes." (E. Selous,Bird Watching, pp. 15-20.)
The same author (ibid., pp. 79, 94) argues that in the fights of two males for one female—with violent emotion on one side and interested curiosity on the other—the attitude of the former "might gradually come to be a display made entirely for the female, and of the latter a greater or less degree of pleasurable excitement raised by it, with a choice in accordance." On this view the interest of the female would first have been directed, not to the plumage, but to the frenzied actions and antics of the male. From these antics in undecorated birds would gradually develop the interest in waving plumes and fluttering wings. Such a dance might come to be of a quite formal and non-courting nature.
Last, we owe to Professor Häcker what may fairly be regarded, in all main outlines, as an almost final statement of the matter. In hisGesang der Vögel(1900) he gives a very clear account of the evolution of bird-song, which he regards as the most essential element in all this group of manifestations, furnishing the key also to the dancing and other antics. Originally the song consists only of call-cries and recognition-notes. Under the parallel influence of natural selection and sexual selection they become at the pairing season reflexes of excitement and thus develop into methods of producing excitement, in the male by themuscular energy required, and in the female through the ear; finally they become play, though here also it is probable that use is not excluded. Thus, so far as the male bird is concerned, bird-song possesses a primary prenuptial significance in attracting the female, a secondary nuptial significance in producing excitement (p. 48). He holds also that the less-developed voices of the females aid in attaining the same end (p. 51). Finally, bird-song possesses a tertiary extranuptial significance (including exercise play, expression of gladness). Häcker points out, at the same time, that the maintenance of some degree of sexual excitement beyond pairing time may be of value for the preservation of the species, in case of disturbance during breeding and consequent necessity for commencing breeding over again.
Such a theory as this fairly coincides with the views brought forward in the preceding pages,—views which are believed to be in harmony with the general trend of thought today,—since it emphasizes the importance of tumescence and all that favors tumescence in the sexual process. The so-called esthetic element in sexual selection is only indirectly of importance. The male's beauty is really a symbol of his force.
It will be seen that this attitude toward the facts of tumescence among birds and other animals includes the recognition of dances, songs, etc., as expressions of "gladness." As such they are closely comparable to the art manifestations among human races. Here, as Weismann in hisGedanken über Musikhas remarked, we may regard the artistic faculty as a by-product: "This [musical] faculty is, as it were, the mental hand with which we play on our own emotional nature, a hand not shaped for this purpose, not due to the necessity for the enjoyment of music, but owing its origin to entirely different requirements."
The psychological significance of these facts has been carefully studied and admirably developed by Groos in his classic works on the play instinct in animals and in men.[27]Going beyond Wallace, Groos deniesconscioussexual selection, but, as he points out, this by no means involves the denial of unconscious selection in the sense that "the female is most easily won by the male who most strongly excites her sexual instincts." Groos further quotes a pregnant generalization of Ziegler: "In all animals a high degree of excitement of the nervous system isnecessary to procreation, and thus we find an excited preludeto procreation widely spread."[28]Such a stage, indeed, as Groos points out, is usually necessary before any markedly passionate discharge of motor energy, as may be observed in angry dogs and the Homeric heroes. While, however, in other motor explosions the prelude may be reduced to a minimum, in courtship it is found in a highly marked degree. The primary object of courtship, Groos insists, is to produce sexual excitement.
It is true that Groos's main propositions were by no means novel. Thus, as I have pointed out, he was at most points anticipated by Tillier. But Groos developed the argument in so masterly a manner, and with so many wide-ranging illustrations, that he has carried conviction where the mere insight of others had passed unperceived. Since Darwin wrote theDescent of Manthe chief step in the development of the theory of sexual selection has been taken by Groos, who has at the same time made it clear that sexual selection is largely a special case of natural selection.[29]The conjunction of the sexes is seen to be an end only to be obtained with much struggle; the difficulty of achieving sexual erethism in both sexes, the difficulty of so stimulating such erethism in the female that her instinctive coyness is overcome, these difficulties the best and most vigorous males,[30]those most adapted in otherrespects to carry on the race, may most easily overcome. In this connection we may note what Marro has said in another connection, when attempting to answer the question why it is that among savages courtship becomes so often a matter in which persuasion takes the form of force. The explanation, he remarks, is yet very simple. Force is the foundation of virility, and its psychic manifestation is courage. In the struggle for life violence is the first virtue. The modesty of women—in its primordial form consisting in physical resistance, active or passive, to the assaults of the male—aided selection by putting to the test man's most important quality, force. Thus it is that when choosing among rivals for her favors a woman attributes value to violence.[31]Marro thus independently confirms the result reached by Groos.
The debate which has for so many years been proceeding concerning the validity of the theory of sexual selection may now be said to be brought to an end. Those who supported Darwin and those who opposed him were, both alike, in part right and in part wrong, and it is now possible to combine the elements of truth on either side into a coherent whole. This is now beginning to be widely recognized; Lloyd Morgan,[32]for instance, has readjusted his position as regards the "pairing instinct" in the light of Groos's contribution to the subject. "The hypothesis of sexual selection," he concludes, "suggests that the accepted male is the one which adequately evokes the pairing impulse.... Courtship may thus be regarded from the physiological point of view as a means of producing the requisite amount of pairing hunger; of stimulating the whole system and facilitating general and special vascular changes; of creating that state of profound and explosive irritability which has for its psychological concomitant or antecedent an imperious and irresistible craving.... Courtship is thusthe strong and steady bending of the bow that the arrow may find its mark in a biological end of the highest importance in the survival of a healthy and vigorous race."