being inserted into the actual sensations. There is a current prejudice to the effect that we dream mostly about the events which have especially preoccupied us during the day. This is sometimes true. But when the psychological life of the waking state thus prolongs itself into sleep, it is because we hardly sleep. A sleep filled with dreams of this kind would be a sleep from which we come out quite fatigued. In normal sleep our dreams concern themselves rather, other things being equal, with the thoughts which we have passed through rapidly or upon objects which we have perceived almost without paying attention to them. If we dream about events of the same day, it is the most insignificant facts, and not the most important, which have the best chance of reappearing.

I agree entirely on this point with the observation of W. Robert, of Delage and of Freud. I was in the street, I was waiting for a street-car, I stood beside the track and did not run the least risk. But if, at the moment when the street-car passed, the idea of possible danger had crossed my mind or even if my body had instinctively recoiled without my having been conscious of feeling any fear, I might dream that night that the car had run over my body. I watch at the bedside of an invalid whose condition is hopeless. If at any moment, perhaps without even being aware of it, I had hoped against hope, I might dream that the invalid was cured. I should dream of the cure, in any case, more probably than that I should dream of the disease. In short, the events which reappear by preference in the dream are those of which we have thought most distractedly. What is there astonishing about that? The ego of the dream is an ego that is relaxed; the memories which it gathers most readily are the memories of relaxation and distraction, those which do not bear the mark of effort.

It is true that in very profound slumber the law that regulates the reappearance of memories may be very different. We know almost nothing of this profound slumber. The dreams which fill it are, as a general rule, the dreams which we forget. Sometimes, nevertheless, we recover something of them. And then it is a very peculiar feeling, strange, indescribable, that we experience. It seems to us that we have returned from afar in space and afar in time. These are doubtless very old scenes, scenes of youth or infancy that we live over then in all their details, with a mood which colors them with that fresh sensation of infancy and youth that we seek vainly to revive when awake.

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.