For a single intelligent observation of the psychic life of a neurotic, a single analysis of a dream must force upon him the unalterable conviction that the most complicated and correct mental operations, to which no one will refuse the name of psychic occurrences, may take place without exciting the consciousness of the person. It is true that the physician does not learn of these unconscious processes until they have exerted such an effect on consciousness as to admit communication or observation. But this effect of consciousness may show a psychic character widely differing from the unconscious process, so that the internal perception cannot possibly recognize the one as a substitute for the other. The physician must reserve for himself the right to penetrate, by a process of deduction, from the effect on consciousness to the unconscious psychic process;