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.  Kuelpe 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.  Fere 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. (Fere, Comptes Rendus Societe de Biologie, July 12, 1902; id., Pathologic des Emotions, pp. 40 et seq.)

Fere 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