Well, now, what attitude are we to take up to these unusual forms of sexual satisfaction? Indignation and expressions of our personal disgust, together with assurances that we do not share these appetites, will obviously not carry us very far. That is not the point at issue. After all, this is a field of phenomena like any other; attempts to turn away and flee from it, on the pretext that these are but rarities and curiosities, could easily be rebutted. On the contrary, the phenomena are common enough and widely distributed. But if it is objected that our views on the sexual life of mankind require no revision on this account, since these things are one and all aberrations and divagations of the sexual instinct, a serious reply will be necessary. If we do not understand these morbid forms of sexuality and cannot relate them to what is normal in sexual life, then neither can we understand normal sexuality. It remains, in short, our undeniable duty to account satisfactorily in theory for the existence of all the perversions described and to explain their relation to normal sexuality, so-called. In this task we can be helped by a point of view, and by two new evidential observations. The first we owe to Ivan Bloch; according to him, the view that all the perversions are “signs of degeneration” is incorrect; because of the evidence existing that such aberrations from the sexual aim, such erratic relationships to the sexual object, have been manifested since the beginning of time through every age of which we have knowledge, in every race from the most primitive to the most highly civilized, and at times have succeeded in attaining to toleration and general prevalence. The two evidential observations have been made in the course of psycho-analytic investigations of neurotic patients; they must undoubtedly influence our conception of sexual perversions in a decisive manner.