From the standpoint of anatomical development and the libido, there are frequently found in the inverted a diminution of the sexual impulse, and a slight stunting of the generative organs. However, this is not preponderately the rule, so it must be recognized that inversion and somatic hermaphroditism (bodily bisexual characters) are quite independent of each other. Freud has demonstrated how neurosis is definitely connected with some phase of the sexual instinct--often the suppression of its normal manifestations. In addition to that, he has shown that the symptoms of neurosis only too frequently represent the converted expression of impulses which in a broader sense may be designated as _perverse_, if they could manifest themselves directly in phantasies and acts without deviating from consciousness. The inference, therefore, is that the symptoms are partially formed at the cost of abnormal sexuality. “The neurosis is, so to say, the negative of the perversion.” Psychoanalysis has brought to light the fact that the well-known fancies of perverts which under favorable conditions are changed into contrivances, the delusional fears of paranoiacs which are in a hostile manner projected on others, and the unconscious fancies of hysterics, agree as to content often in the minutest details. This illustrates that the unconscious mental processes of all persons have much that is held in common, based upon biological promptings that are the common property of mankind. The varied ways in which they manifest themselves are due to the different trends of disposition, mental aptitude, environmental influences, etc. According to the psychoanalytic hypothesis, the sexual impulse of the psychoneurotic shows all the aberrations of morbid sexual life. This principle may be summarized as follows (after Freud): (a) In all the neurotics without exception there is evident feelings of _inversion in the unconscious psychic life, fixation of libido on persons of the same sex_. It is impossible, without a deep and searching discussion, adequately to appreciate the significance of this factor for the formation of the picture of the disease; but it may be safely asserted that the unconscious propensity to inversion is never wanting and is particularly of immense service in explaining male hysteria. (b) All the inclinations to anatomical transgression can be demonstrated in psychoneurotics in the unconscious and as symptom-creators. Of special frequency and intensity are those which impart to the mouth and the mucous membrane of the anus the role of genitals.