studied the fundamental works on psychoanalysis. In spite of the fact that Freud's theory of neurosis has been worked out in great detail, it cannot be said to be, on the whole, very clear or easily accessible. This justifies my giving you a very short abstract of his fundamental views concerning the theory of neurosis. You are aware that the original theory that hysteria and the related neuroses take their origin in a trauma or shock of sexual character in early childhood, was given up about fifteen years ago. It soon became obvious that the sexual trauma could not be the real cause of a neurosis, since trauma is found so universally; there is scarcely a human being who has not had some sexual shock in early youth, and yet comparatively few have incurred a neurosis in later life. Freud himself soon became aware that several of the patients who related an early traumatic event, had only invented the story of a so-called trauma; it had never taken place in reality, and was a mere creation of phantasy. Moreover, on further investigation it became quite obvious that even a trauma which had actually occurred was not always responsible for the whole of the neurosis, although it does sometimes look as if the structure of the neurosis depended entirely upon the trauma. If a neurosis were the inevitable consequence of a trauma it would be quite incomprehensible why neurotics are not incomparably more numerous. This apparently heightened shock-effect was clearly based upon the _exaggerated and morbid phantasy_ of the patient. Freud also saw that this same phantasy manifested itself in relatively early bad habits, which he called infantile perversities. His new conception of the ætiology of a neurosis was based upon this further understanding and traced the neurosis back to some sexual activity in early infancy; this conception led on to his recent view that the neurotic is "fixed" to a certain period of his early infancy, because he still seems to preserve some trace of it, direct or indirect, in his mental attitude. Freud also makes the attempt to classify or to differentiate the neuroses, including dementia præcox, according to the stage of the infantile development in which the fixation took place. From the standpoint of this theory, the neurotic appears to be entirely dependent upon his infantile past, and all his troubles in later life, his moral conflicts, and deficiencies, seem to be derived from the powerful influence of that period. The therapy and its main preoccupation are in full accord with this view, and are chiefly concerned with the unravelling of this infantile fixation, which is understood as an unconscious attachment of the sexual libido to certain infantile phantasies and habits.