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 manoeuvres, 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.” (Fere, 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 aesthetic; 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.  Fere, 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