number of patients stated that they had suffered a distinct loss
of sexual feeling. Lawson Tait, however, throws doubts on the
reliability of the Committee's results, which were based on the
statements of unintelligent hospital patients.

I may quote the following remarks from a communication sent to me
by an experienced physician in Australia: "No rule can be laid
down in cases in which both ovaries have been extirpated. Some
women say that, though formerly passionate, they have since
become quite indifferent, but I am of opinion that the majority
of women who have had prior sexual experience retain desire and
gratification in an equal degree to that they had before
operation. I know one case in which a young girl hardly 19 years
old, who had been accustomed to congress for some twelve months,
had trouble which necessitated the removal of the ovaries and
tubes on both sides. Far from losing all her desire or
gratification, both were very materially increased in intensity.
Menstruation has entirely ceased, without loss of femininity in
either disposition or appearance. During intercourse, I am told,
there is continuous spasmodic contraction of various parts of the
vagina and vulva."

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 these _Studies_
I 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 in _Medical 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 stronger than 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 the sexual 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 is a 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's _Sur 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; also _Ausgewahlte
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 dictum _omne animal post coitum
triste_ may 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 the special 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 complete mutual 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. That the 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 the _impulse 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 the _impulse 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 serious and 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 the _Descent of Man_ reveals 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 habitually or 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 to _Locustidæ_, 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 the _Descent 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, especially with 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 esthetic
choice 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 runs _pari passu_
with 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 injected
with 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's _Physiology 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 these _Studies_.)

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; also _Geschlecht 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 his
_Tropical Nature_ he 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
his _Darwinism_) 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 subject in 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 factor in
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 entitled _The 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 the antics 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
his _Gesang 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 the
muscular 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 his _Gedanken über Musik_ has 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 denies _conscious_
sexual 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 is _necessary to
procreation_, and thus we find an excited prelude to 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 the _Descent
of Man_ the 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 other respects 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 thus
the 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."

Having thus viewed the matter broadly, we may consider in detail
a few examples of the process of tumescence among the lower
animals and man, for, as will be seen, the process in both is
identical. As regards animal courtship, the best treasury of
facts is Brehm's _Thierleben_, while Büchner's _Liebe und
Liebes-Leben in der Thierwelt_ is a useful summary; the admirable
discussion of bird-dancing and other forms of courtship in
Häcker's _Gesang der Vögel_, chapter iv, may also be consulted.
As regards man, Wallaschek's _Primitive Music_, chapter vii,
brings together much scattered material, and is all the more
valuable since the author rejects any form of sexual selection;
Hirn's _Origins of Art_, chapter xvii, is well worth reading, and
Finck's _Primitive Love and Love-stories_ contains a large amount
of miscellaneous information. I have preferred not to draw on any
of these easily accessible sources (except that in one or two