of the mental field consequent on enlarging experience the instinctive activity is externalized, and its object of interest changes so that the child acquires a specific inclination towards other individuals without distinction of sex; finally, as a last stage of development the instinctive inclination is localized to members of the opposite sex. This series of transformations is regarded as normal by Freud, and as essential to the appearance of the “normal” adult type. The evolution of this series is sensitive to interference by outside influences, and any disturbance of it either by way of anticipation or delay will have profound effects upon the ultimate character and temperament of the subject. The psychical energy of an instinct so important as that of sex is very great, and is not dissipated by the forces of repression brought to bear upon it, but transformed into activities ostensibly quite different and directed into channels having no obvious connection with their source. It is a fundamental characteristic of the mind to be able to accept these substitutes for the actual indulgence of the instinct, and to enjoy a symbolical gratification in manifestations which have no overt sexual significance. When development proceeds normally the {74} surplus energy of the sex instinct finds an outlet in activities of social value—æsthetic, poetic, altruistic; when development is interfered with the outflow of energy is apt to result in definite disease of the mind or in peculiarities of character scarcely to be distinguished therefrom.
Thus the mind of the adult, according to Freud, in addition to activities which are conscious and fully accessible to the subject, carries on activities and holds memories which are unconscious and totally inaccessible to the subject by any ordinary method of introspection. Between these two fields there is a barrier sedulously guarded by certain repressive forces. The unconscious is the realm of all the experiences, memories, impulses, and inclinations which during the subject’s life have been condemned by the standards of the conscious, have proved incompatible with it and have therefore been outlawed from it. This banishment in no way deprives these excluded mental processes of their energy, and they constantly