of the connection between the sexual embrace and tickling is indicated by the fact that in some languages, as in that of the Fuegians,[12] the same word is applied to both.  That ordinary tickling is not sexual is due to the circumstances of the case and the regions to which the tickling is applied.  If, however, the tickling is applied within the sexual sphere, then there is a tendency for orgasm to take place instead of laughter.  The connection which, through the phenomena of tickling, laughter thus bears to the sexual sphere is well indicated, as Groos has pointed out, by the fact that in sexually-minded people sexual allusions tend to produce laughter, this being the method by which they are diverted from the risks of more specifically sexual detumescence.[13]

Reference has been made to the view of Alrutz, according to which tickling is a milder degree of itching.  It is more convenient and probably more correct to regard itching or pruritus, as it is termed in its pathological forms, as a distinct sensation, for it does not arise under precisely the same conditions as tickling nor is it relieved in the same way.  There is interest, however, in pointing out in this connection that, like tickling, itching has a real parallelism to the specialized sexual sensations.  Bronson, who has very ably interpreted the sensations of itching (New York Neurological Society, October 7, 1890; Medical News, February 14, 1903, and summarized in the British Medical Journal, March 7, 1903; and elsewhere), regards it as a perversion of the sense of touch, a dysaesthesia due to obstructed nerve-excitation with imperfect conduction of the generated force into correlated nervous energy.  The scratching which relieves itching directs the nervous energy into freer channels, sometimes substituting for the pruritus either painful or voluptuous sensations.  Such voluptuous sensations may be regarded as a generalized aphrodisiac sense comparable to the specialized sexual orgasm.  Bronson refers to the significant fact that itching occurs so frequently in the sexual region, and states that sexual neurasthenia is sometimes the only discoverable cause of genital and anal pruritus. (Cf. discussion on pruritus, British Medical Journal, November 30, 1895.) Gilman, again (American Journal of Psychology, vi, p. 22), considers that scratching, as well as sneezing, is comparable to coitus.

The sexual embrace has an intimate connection with the phenomena of ticklishness which could not fail to be recognized.  This connection is, indeed, the basis of Spinoza’s famous definition of love,—­“Amor est titillatio quaedam concomitante idea causae externae,”—­a statement which seems to be reflected in Chamfort’s definition of love as “l’echange de deux fantaisies, et le contact de deux epidermes.”  The sexual act, says Gowers, is, in fact, a skin reflex.[14] “The sexual parts,” Hall and Allin state, “have a ticklishness as unique as their function