We subsequently discussed the psychic results of a feeling of gratification, and we might at the same time have introduced the second assumption, viz. that accumulation of excitement — following certain modalities that do not concern us — is perceived as pain and sets the apparatus in motion in order to reproduce a feeling of gratification in which the diminution of the excitement is perceived as pleasure. Such a current in the apparatus which emanates from pain and strives for pleasure we call a wish. We have said that nothing but a wish is capable of setting the apparatus in motion, and that the discharge of excitement in the apparatus is regulated automatically by the perception of pleasure and pain. The first wish must have been an hallucinatory occupation of the memory for gratification. But this hallucination, unless it were maintained to