THE SEXUAL ABERRATIONS 1 THE fact of the existence of sexual needs in human beings and animals is expressed in biology by the assumption of a'sexual instinct,, on the analogy of the instinct of nutrition, that is of ager. Everyday language possesses no counterpart to the word hunger, but science makes use of the word",for that purpose. 2 Popular opinion has quite definite ideas about the nature ar characteristics of this sexual instinct. It is generally understood to be absent in childhood, to set in at the time of puberty in revealed in the manifestations of an irresistible attraction exer- cised by one sex upon the other; while its aim is presumed to be xual union, or at all events actions leading in that direction We have every reason to believe, however, that these views give a very false picture of the true situation. If we look into them more closely we shall find that they contain a number of errors, inaccuracies and hasty conclusions I shall at this point introduce two technical terms. Let call the person from whom sexual attraction proceeds the sexual i The information contained in this first essay is derived from the Schrenck-Notzing, Lowenfeld, Eulenburg, Bloch and Hirschfeld, and from the ja published under the dire tion of the last-named author. Since full bibliographies of the remaining the subject will be found in th ences. [Added 1910: ]The obtained from the psycho-analytic in gation of inverts are based upon material supplied to me by rd in the gerr