It is upon this profound slumber that psychology ought to direct its efforts, not only to study the mechanism of unconscious memory, but to examine the more mysterious phenomena which are raised by "psychical research." I do not dare express an opinion upon phenomena of this class, but I cannot avoid attaching some importance to the observations gathered by so rigorous a method and with such indefatigable zeal by the Society for Psychical Research. If telepathy influences our dreams, it is quite likely that in this profound slumber it would have the greatest chance to manifest itself. But I repeat, I cannot express an opinion upon this point. I have gone forward with you as far as I can; I stop upon the threshold of the mystery. To explore the most secret depths of the unconscious, to labor in what I have just called the subsoil of consciousness, that will be the principal task of psychology in the century which is opening. I do not doubt that wonderful discoveries await it there, as important perhaps as have been in the preceding centuries the discoveries of the physical and natural sciences. That at least is the promise which I make for it, that is the wish that in closing I have for it. FOOTNOTES: [1] Author's note (1913). This would be the place where especially will intervene those "repressed desires" which Freud and certain other psychologists, especially in America, have studied with such penetration and ingenuity. (See in particular the recent volumes of the _Journal of Abnormal Psychology_, published in Boston by Dr. Morton Prince.) When the above address was delivered (1901) the work of Freud on dreams (_Die Traumdeutung_) had been already published, but "psycho-analysis" was far from having the development that it has to-day. (H. B.)