We are accustomed to regard the skin as mainly owing its existence

We are accustomed to regard the skin as mainly owing its existence to the need for the protection of the delicate vessels, nerves, viscera, and muscles underneath. Undoubtedly it performs, and by its tough and elastic texture is well fitted to perform, this extremely important service. But the skin is not merely a method of protection against the external world; it is also a method of bringing us into sensitive contact with the external world. It is thus, as the organ of touch, the seat of the most widely diffused sense we possess, and, moreover, the sense which is the most ancient and fundamental of all—the mother of the other senses.

It is scarcely necessary to insist that the primitive nature of the sensory function of the skin with the derivative nature of the other senses, is a well ascertained and demonstrable fact. The lower we descend in the animal scale, the more varied we find the functions of the skin to be, and if in the higher animals much of the complexity has disappeared, that is only because the specialization of the various skin regions into distinct organs has rendered this complexity unnecessary. Even yet, however, in man himself the skin still retains, in a more or less latent condition, much of its varied and primary power, and the analysis of pathological and even normal phenomena serves to bring these old powers into clear light.

Woods Hutchinson (Studies in Human and Comparative Pathology, 1901, Chapters VII and VIII) has admirably set forth the immense importance of the skin, as in the first place "a tissue which is silk to the touch, the most exquisitely beautiful surface in the universe to the eye, and yet a wall of adamant against hostile attack. Impervious alike, by virtue of its wonderful responsive vitality, to moisture and drought, cold and heat, electrical changes, hostile bacteria, the most virulent of poisons and the deadliest of gases, it is one of the real Wonders of the World. More beautiful than velvet, softer and more pliable than silk, more impervious than rubber, and more durable under exposure than steel, well-nigh as resistant to electric currents as glass, it is one of the toughest and most dangerproof substances in the three kingdoms of nature" (although, as this author adds, we "hardly dare permit it to see the sunlight or breathe the open air"). But it is more than this. It is, as Woods Hutchinson expresses it, the creator of the entire body; its embryonic infoldings form the alimentary canal, the brain, the spinal cord, while every sense is but a specialization of its general organic activity. It is furthermore a kind of "skin-heart," promoting the circulation by its own energy; it is the great heat-regulating organ of the body; it is an excretory organ only second to the kidneys, which descend from it, and finally it still remains the seat of touch.

It may be added that the extreme beauty of the skin as a surface is very clearly brought out by the inadequacy of the comparisons commonly used in order to express its beauty. Snow, marble, alabaster, ivory, milk, cream, silk, velvet, and all the other conventional similes furnish surfaces which from any point of view are incomparably inferior to the skin itself. (Cf. Stratz, Die Schönheit des Weiblichen Körpers, Chapter XII.)

With reference to the extraordinary vitality of the skin, emphasized by Woods Hutchinson, it may be added that, when experimenting on the skin with the electric current, Waller found that healthy skin showed signs of life ten days or more after excision. It has been found also that fragments of skin which have been preserved in sterile fluid for even as long as nine months may still be successfully transplanted on to the body. (British Medical Journal, July 19, 1902.)

Everything indicates, remark Stanley Hall and Donaldson ("Motor Sensations in the Skin," Mind, 1885), that the skin is "not only the primeval and most reliable source of our knowledge of the external world or the archæological field of psychology," but a field in which work may shed light on some of the most fundamental problems of psychic action. Groos (Spiele der Menschen, pp. 8-16) also deals with the primitive character of touch sensations.

Touch sensations are without doubt the first of all the sensory impressions to prove pleasurable. We should, indeed, expect this from the fact that the skin reflexes have already appeared before birth, while a pleasurable sensitiveness of the lips is doubtless a factor in the child's response to the contact of the maternal nipple. Very early memories of sensory pleasure seem to be frequently, perhaps most frequently, tactile in character, though this fact is often disguised in recollection, owing to tactile impression being vague and diffused; there is thus in Elizabeth Potwin's "Study of Early Memories" (Psychological Review, November, 1901) no separate group of tactile memories, and the more elaborate investigation by Colegrove ("Individual Memories," American Journal of Psychology, January, 1899) yields no decisive results under this head. See, however, Stanley Hall's valuable study, "Some Aspects of the Early Sense of Self," American Journal of Psychology, April, 1898. Külpe has a discussion of the psychology of cutaneous sensations (Outlines of Psychology [English translation], pp. 87 et seq.)

Harriet Martineau, at the beginning of her Autobiography, referring to the vivid character of tactile sensations in early childhood, remarks, concerning an early memory of touching a velvet button, that "the rapture of the sensation was really monstrous." And a lady tells me that one of her earliest memories at the age of 3 is of the exquisite sensation of the casual contact of a cool stone with the vulva in the act of urinating. Such sensations, of course, cannot be termed specifically sexual, though they help to furnish the tactile basis on which the specifically sexual sensations develop.

The elementary sensitiveness of the skin is shown by the fact that moderate excitation suffices to raise the temperature, while Heidenhain and others have shown that in animals cutaneous stimuli modify the sensibility of the brain cortex, slight stimulus increasing excitability and strong stimulus diminishing it. Féré has shown that the slight stimulus to the skin furnished by placing a piece of metal on the arm or elsewhere suffices to increase the output of work with the ergograph. (Féré, Comptes Rendus Société de Biologie, July 12, 1902; id., Pathologic des Emotions, pp. 40 et seq.)

Féré found that the application of a mustard plaster to the skin, or an icebag, or a hot-water bottle, or even a light touch with a painter's brush, all exerted a powerful effect in increasing muscular work with the ergograph. "The tonic effect of cutaneous excitation," he remarks, "throws light on the psychology of the caress. It is always the most sensitive parts of the body which seek to give or to receive caresses. Many animals rub or lick each other. The mucous surfaces share in this irritability of the skin. The kiss is not only an expression of feeling; it is a means of provoking it. Cataglottism is by no means confined to pigeons. The tonic value of cutaneous stimulation is indeed a commonly accepted idea. Wrestlers rub their hands or limbs, and the hand-shake also is not without its physiological basis.

"Cutaneous excitations may cause painful sensations to cease. Many massage practices which favor work act chiefly as sensorial stimulants; on this account many nervous persons cannot abandon them, and the Greeks and Romans found in massage not only health, but pleasure. Lauder Brunton regards many common manœuvres, like scratching the head and pulling the mustache, as methods of dilating the bloodvessels of the brain by stimulating the facial nerve. The motor reactions of cutaneous excitations favor this hypothesis." (Féré, Travail et Plaisir, Chapter XV, "Influence des Excitations du Toucher sur le Travail.")

The main characteristics of the primitive sense of touch are its wide diffusion over the whole body and the massive vagueness and imprecision of the messages it sends to the brain. This is the reason, why it is, of all the senses, the least intellectual and the least æsthetic; it is also the reason why it is, of all the senses, the most-profoundly emotional. "Touch," wrote Bain in his Emotions and Will, "is both the alpha and the omega of affection," and he insisted on the special significance in this connection of "tenderness"—a characteristic emotional quality of affection which is directly founded on sensations of touch. If tenderness is the alpha of affection, even between the sexes, its omega is to be found in the sexual embrace, which may be said to be a method of obtaining, through a specialized organization of the skin, the most exquisite and intense sensations of touch.

"We believe nothing is so exciting to the instinct or mere passions as the presence of the hand or those tactile caresses which mark affection," states the anonymous author of an article on "Woman in her Psychological Relations," in the Journal of Psychological Medicine, 1851. "They are the most general stimuli in lower animals. The first recourse in difficulty or danger, and the primary solace in anguish, for woman is the bosom of her husband or her lover. She seeks solace and protection and repose on that part of the body where she herself places the objects of her own affection. Woman appears to have the same instinctive impulse in this respect all over the world."

It is because the sexual orgasm is founded on a special adaptation and intensification of touch sensations that the sense of touch generally is to be regarded as occupying the very first place in reference to the sexual emotions. Féré, Mantegazza, Penta, and most other writers on this question are here agreed. Touch sensations constitute a vast gamut for the expression of affection, with at one end the note of minimum personal affection in the brief and limited touch involved by the conventional hand-shake and the conventional kiss, and at the other end the final and intimate contact in which passion finds the supreme satisfaction of its most profound desire. The intermediate region has its great significance for us because it offers a field in which affection has its full scope, but in which every road may possibly lead to the goal of sexual love. It is the intimacy of touch contacts, their inevitable approach to the threshold of sexual emotion, which leads to a jealous and instinctive parsimony in the contact of skin and skin and to the tendency with the increased sensitiveness of the nervous system involved by civilization to restrain even the conventional touch manifestation of ordinary affection and esteem. In China fathers leave off kissing their daughters while they are still young children. In England the kiss as an ordinary greeting between men and women—a custom inherited from classic and early Christian antiquity—still persisted to the beginning of the eighteenth century. In France the same custom existed in the seventeenth century, but in the middle of that century was beginning to be regarded as dangerous, while at the present time the conventional kiss on the cheek is strictly differentiated from the kiss on the mouth, which is reserved for lovers. Touch contacts between person and person, other than those limited and defined by custom, tend to become either unpleasant—as an undesired intrusion into an intimate sphere—or else, when occurring between man and woman at some peculiar moment, they may make a powerful reverberation in the emotional and more specifically sexual sphere. One man falls in love with his future wife because he has to carry her upstairs with a sprained ankle. Another dates his love-story from a romp in which his cheek accidentally came in contact with that of his future wife. A woman will sometimes instinctively strive to attract the attention of the man who appeals to her by a peculiar and prolonged pressure of the hand—the only touch contact permitted to her. Dante, as Penta has remarked, refers to "sight or touch" as the two channels through which a woman's love is revived (Purgatorio, VIII, 76). Even the hand-shake of a sympathetic man is enough in some chaste and sensitive women to produce sexual excitement or sometimes even the orgasm. The cases in which love arises from the influence of stimuli coming through the sense of touch are no doubt frequent, and they would be still more frequent if it were not that the very proximity of this sense to the sexual sphere causes it to be guarded with a care which in the case of the other senses it is impossible to exercise. This intimacy of touch and the reaction against its sexual approximations leads to what James has called "the antisexual instinct, the instinct of personal isolation, the actual repulsiveness to us of the idea of intimate contact with most of the persons we meet, especially those of our own sex." He refers in this connection to the unpleasantness of the sensation felt on occupying a seat still warm from the body of another person. The Catholic Church has always recognized the risks of vuluptuous emotion involved in tactile contacts, and the facility with which even the most innocent contacts may take on a libidinous character.

The following observations were written by a lady (aged 30) who has never had sexual relationships: "I am only conscious of a very sweet and pleasurable emotion when coming in contact with honorable men, and consider that a comparison can be made between the idealism of such emotions and those of music, of beauties of Nature, and of productions of art. While studying and writing articles upon a new subject I came in contact with a specialist, who rendered me considerable aid, and, one day, while jointly correcting a piece of work, he touched my hand. This produced a sweet and pure sensation of thrill through the whole system. I said nothing; in fact, was too thrilled for speech; and never to this day have shown any responsive action, but for months at certain periods, generally twice a month, I have experienced the most pleasurable emotions. I have seen this friend twice since, and have a curious feeling that I stand on one side of a hedge, while he is on the other, and, as neither makes an approach, pleasure of the highest kind is experienced, but not allowed to go beyond reasonable and health-giving bounds. In some moments I feel overcome by a sense of mastery by this man, and yet, feeling that any approach would be undignified, some pleasure is experienced in restraining and keeping within proper bounds this passional emotion. All these thrills of pleasurable emotion possess a psychic value, and, so long as the nervous system is kept in perfect health, they do not seem to have the power to injure, but rather one is able to utilize the passionate emotions as weapons for pleasure and work."

Various parts of the skin surface appear to have special sexual sensitiveness, peculiarly marked in many individuals, especially women; so that, as Féré remarks (L'Instinct Sexuel, second edition, 1902, p. 130), contact stimulation of the lips, lobe of ear, nape of neck, little finger, knee, etc., may suffice even to produce the orgasm. Some sexually hyperæsthetic women, as has already been noted, experience this when shaking hands with a man who is attractive to them. In some neurotic persons this sensibility, as Féré shows, may exist in so morbid a degree that even the contact of the sensitive spot with unattractive persons or inanimate objects may produce the orgasm. In this connection reference may be made to the well-known fact that in some hysterical subjects there are so-called "erogenous zones" simple pressure on which suffices to evoke the complete orgasm. There is, perhaps, some significance, from our present point of view, in the fact that, as emphasized by Savill ("Hysterical Skin Symptoms," Lancet, January 30, 1904), the skin is one of the very best places to study hysteria.

The intimate connection between the skin and the sexual sphere is also shown in pathological conditions of the skin, especially in acne as well as simple pimples on the face. The sexual development of puberty involves a development of hair in various regions of the body which previously were hairless. As, however, the sebaceous glands on the face and elsewhere are the vestiges of former hairs and survive from a period when the whole body was hairy, they also tend to experience in an abortive manner this same impulse. Thus, we may say that, with the development of the sexual organs at puberty, there is correlated excitement of the whole pilo-sebaceous apparatus. In the regions where this apparatus is vestigial, and notably in the face, this abortive attempt of the hair-follicles and their sebaceous appendages to produce hairs tends only to disorganization, and simple comedones or pustular acne pimples are liable to occur. As a rule, acne appears about puberty and dies out slowly during adolescence. While fairly common in young women, it is usually much less severe, but tends to be exacerbated at the menstrual periods; it is also apt to appear at the change of life. (Stephen Mackenzie, "The Etiology and Treatment of Acne Vulgaris," British Medical Journal, September 29, 1894. Laycock [Nervous Diseases of Women, 1840, p. 23] pointed out that acne occurs chiefly in those parts of the surface covered by sexual hair. A lucid account of the origin of acne will be found in Woods Hutchinson's Studies in Human and Comparative Pathology, pp. 179-184. G. J. Engelmann ["The Hystero-neuroses," Gynæcological Transactions, 1887, pp. 124 et seq.] discusses various pathological disorders of the skin as reflex disturbances originating in the sexual sphere.)

The influence of menstruation in exacerbating acne has been called in question, but it seems to be well established. Thus, Bulkley ("Relation between Certain Diseases of the Skin and the Menstrual Function," Transactions of the Medical Society of New York, 1901, p. 328) found that, in 510 cases of acne in women, 145, or nearly one-third, were worse about the monthly period. Sometimes it only appeared during menstruation. The exacerbation occurred much more frequently just before than just after the period. There was usually some disturbance of menstruation. Various other disorders of the skin show a similar relationship to menstruation.

It has been asserted that masturbation is a frequent or constant cause of acne at puberty. (See, e.g., discussion in British Medical Journal, July, 1882.) This cannot be accepted. Acne very frequently occurs without masturbation, and masturbation is very frequently practiced without producing acne. At the same time we may well believe that at the period of puberty, when the pilo-sebaceous system is already in sensitive touch with the sexual system, the shock of frequently repeated masturbation may (in the same way as disordered menstruation) have its repercussion on the skin. Thus, a lady has informed me that at about the age of 18 she found that frequently repeated masturbation was followed by the appearance of comedones.