The popular theory of the sexual impulse corresponds closely to the poetic fable of dividing the person into two halves--man and woman--who strive to become reunited through love. It is therefore very surprising to hear that there are men for whom the sexual object is not woman but man, and that there are women for whom it is not man but woman. Such _persons_ are called contrary sexuals, or better, inverts; the _condition_, that of inversion. The number of such individuals is considerable though difficult of accurate determination.[3] A. _Inversion_ *The Behavior of Inverts.*--The above-mentioned persons behave in many ways quite differently. (_a_) They are absolutely inverted; _i.e._, their sexual object must be always of the same sex, while the opposite sex can never be to them an object of sexual longing, but leaves them indifferent or may even evoke sexual repugnance. As men they are unable, on account of this repugnance, to perform the normal sexual act or miss all pleasure in its performance. (_b_) They are amphigenously inverted (psychosexually hermaphroditic); _i.e._, their sexual object may belong indifferently to either the same or to the other sex. The inversion lacks the character of exclusiveness. (_c_) They are occasionally inverted; _i.e._, under certain external conditions, chief among which are the inaccessibility of the normal sexual object and initiation, they are able to take as the sexual object a person of the same sex and thus find sexual gratification. The inverted also manifest a manifold behavior in their judgment about the peculiarities of their sexual impulse. Some take the inversion as a matter of course, just as the normal person does regarding his libido, firmly demanding the same rights as the normal. Others, however, strive against the fact of their inversion and perceive in it a morbid compulsion.[4] Other variations concern the relations of time. The characteristics of the inversion in any individual may date back as far as his memory goes, or they may become manifest to him at a definite period before or after puberty.[5] The character is either retained throughout life, or it occasionally recedes or represents an episode on the road to normal development. A periodical fluctuation between the normal and the inverted sexual object has also been observed. Of special interest are those cases in which the libido changes, taking on the character of inversion after a painful experience with the normal sexual object. These different categories of variation generally exist independently of one another. In the most extreme cases it can regularly be assumed that the inversion has existed at all times and that the person feels contented with his peculiar state.