Foremost in the second group are those perverts whose sexual desires aim at the performance of an act which normally is but an introductory or preparatory one. They are those who seek gratification in looking and touching, or in watching the other person’s most intimate doings; or those who expose parts of their own bodies which should be concealed, in the vague expectation of being rewarded by a similar action on the part of the other. Then come the incomprehensible sadists, in whom all affectionate feeling strains towards the one goal of causing their object pain and torture, ranging in degree from mere indications of a tendency to humiliate the other up to the infliction of severe bodily injuries. Then, as though complementary to these, come the masochists whose only longing is to suffer, in real or in symbolic form, humiliations and tortures at the hands of the loved object. There are others yet, in whom several abnormal characteristics of this kind are combined and interwoven with one another. Finally, we learn that the persons belonging to each of these groups may be divided again: into those who seek their particular form of sexual satisfaction in reality and those who are satisfied merely to imagine it in their own minds, needing no real object at all but being able to substitute for it a creation of phantasy. There is not the slightest possible doubt that these mad, extraordinary and horrible things do actually constitute the sexual activities of these people. Not merely do they themselves so regard them, recognizing their substitutive character; but we also have to acknowledge that they play the same part in their lives as normal sexual satisfaction plays in ours, exacting the same, often excessive, sacrifices. It is possible to trace out, both broadly and in great detail, where these abnormalities merge into the normal and where they diverge from it. Nor will it escape you that that quality of impropriety which adheres inevitably to a sexual activity is not absent from these forms of it: in most of them it is intensified to the point of odium.