I must still add something more in order to complete our assessment of the sexual perversions. Abominated as they are, sharply distinguished from normal sexual activity as they may be, simple observation will show that very rarely is one feature or another of them absent from the sexual life of a normal person. The kiss to begin with has some claim to be called a perverse act, for it consists of the union of the two erotogenic mouth zones instead of the two genital organs. But no one condemns it as perverse; on the contrary, in the theatre it is permitted as a refined indication of the sexual act. Nevertheless, kissing is a thing that can easily become an absolute perversion—namely, when it occurs in such intensity that orgasm and emission directly accompany it, which happens not at all uncommonly. Further, it will be found that gazing at and handling the object are in one person an indispensable condition of sexual enjoyment, while another at the height of sexual excitement pinches or bites; that in another lover not always the genital region, but some other bodily region in the object, provokes the greatest excitement, and so on in endless variety. It would be absurd to exclude people with single idiosyncrasies of this kind from the ranks of the normal and place them among perverts; rather, it becomes more and more clear that what is essential to the perversions lies, not in the overstepping of the sexual aim, not in the replacement of the genitalia, not always even in the variations in the object, but solely in the _exclusiveness_ with which these deviations are maintained, so that the sexual act which serves the reproductive process is rejected altogether. In so far as perverse performances are included in order to intensify or to lead up to the performance of the normal sexual act, they are no longer actually perverse. Facts of the kind just described naturally tend to diminish the gulf between normal and perverse sexuality very considerably. The obvious inference is that normal sexuality has arisen, out of something existing prior to it, by a process of discarding some components of this material as useless, and by combining the others so as to subordinate them to a new aim, that of reproduction.