For reasons which we shall discuss later we will take as a model of the infantile sexual manifestations thumbsucking (pleasure-sucking), to which the Hungarian pediatrist, Lindner, has devoted an excellent essay.[9] *Thumbsucking.*--Thumbsucking, which manifests itself in the nursing baby and which may be continued till maturity or throughout life, consists in a rhythmic repetition of sucking contact with the mouth (the lips), wherein the purpose of taking nourishment is excluded. A part of the lip itself, the tongue, which is another preferable skin region within reach, and even the big toe--may be taken as objects for sucking. Simultaneously, there is also a desire to grasp things, which manifests itself in a rhythmical pulling of the ear lobe and which may cause the child to grasp a part of another person (generally the ear) for the same purpose. The pleasure-sucking is connected with an entire exhaustion of attention and leads to sleep or even to a motor reaction in the form of an orgasm.[10] Pleasure-sucking is often combined with a rubbing contact with certain sensitive parts of the body, such as the breast and external genitals. It is by this road that many children go from thumb-sucking to masturbation. Lindner himself has recognized the sexual nature of this action and openly emphasized it. In the nursery thumbsucking is often treated in the same way as any other sexual "naughtiness" of the child. A very strong objection was raised against this view by many pediatrists and neurologists which in part is certainly due to the confusion of the terms "sexual" and "genital." This contradiction raises the difficult question, which cannot be rejected, namely, in what general traits do we wish to recognize the sexual manifestations of the child. I believe that the association of the manifestations into which we gained an insight through psychoanalytic investigation justify us in claiming thumbsucking as a sexual activity and in studying through it the essential features of the infantile sexual activity. *Autoerotism.*--It is our duty here to arrange this state of affairs differently. Let us insist that the most striking character of this sexual activity is that the impulse is not directed against other persons but that it gratifies itself on its own body; to use the happy term invented by Havelock Ellis, we will say that it is autoerotic.[11]