The intellectual element in tickling conies out in its connection with laughter and the sense of the comic, of which it may be said to constitute the physical basis. While we are not here concerned with laughter and the comic sense,--a subject which has lately attracted considerable attention,--it may be instructive to point out that there is more than an analogy between laughter and the phenomena of sexual tumescence and detumescence. The process whereby prolonged tickling, with its nervous summation and irradiation and accompanying hyperæmia, finds sudden relief in an explosion of laughter is a real example of tumescence--as it has been defined in the study in another volume entitled "An Analysis of the Sexual Impulse"--resulting finally in the orgasm of detumescence. The reality 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]