which the dreaming ego would answer, "I was doing nothing; and this is just where you and I differ from one another. You imagine that in order to hear a dog barking, and to know that it is a dog that barks, you have nothing to do. That is a great mistake. You accomplish, without suspecting it, a considerable effort. You take your entire memory, all your accumulated experience, and you bring this formidable mass of memories to converge upon a single point, in such a way as to insert exactly in the sounds you heard that one of your memories which is the most capable of being adapted to it. Nay, you must obtain a perfect adherence, for between the memory that you evoke and the crude sensation that you perceive there must not be the least discrepancy; otherwise you would be just dreaming. This adjustment you can only obtain by an effort of the memory and an effort of the perception, just as the tailor who is trying on a new coat pulls together the pieces of cloth that he adjusts to the shape of your body in order to pin them. You exert, then, continually, every moment of the day, an enormous effort. Your life in a waking state is a life of labor, even when you think you are doing nothing, for at every minute you have to choose and every minute exclude. You choose among your sensations, since you reject from your consciousness a thousand subjective sensations which come back in the night when you sleep. You choose, and with extreme precision and delicacy, among your memories, since you reject all that do not exactly suit your present state. This choice which you continually accomplish, this adaptation, ceaselessly renewed, is the first and most essential condition of what is called common sense. But all this keeps you in a state of uninterrupted tension. You do not feel it at the moment, any more than you feel the pressure of the atmosphere, but it fatigues you in the long run. Common sense is very fatiguing.

"So, I repeat, I differ from you precisely in that I do nothing. The effort that you give without cessation I simply abstain from giving. In place of attaching myself to life, I detach myself from it. Everything has become indifferent to me. I have become disinterested in everything. To sleep is to become disinterested. One sleeps to the exact extent to which he becomes disinterested. A mother who sleeps by the side of her child will not stir at the sound of thunder, but the sigh of the child will wake her. Does she really sleep in regard to her child? We do not sleep in regard to what continues to interest us.

"You ask me what it is that I do when I dream? I will tell you what you do when you are awake. You take me, the me of dreams, me the totality of your past, and you force me, by making me smaller and smaller, to fit into the little circle that you trace around your present action. That is what it is to be awake. That is what it is to live the normal psychical life. It is to battle. It is to will. As for the dream, have you really any need that I should explain it? It is the state into which you naturally fall when you let yourself go, when you no longer have the power to concentrate yourself upon a single point, when you have ceased to will. What needs much more to be explained is the marvelous mechanism by which at any moment your will obtains instantly, and almost unconsciously, the concentration of all that you have within you upon one and the same point, the point that interests you. But to explain this is the task of normal psychology, of the psychology of waking, for willing and waking are one and the same thing."

This is what the dreaming ego would say. And it would tell us a great many other things still if we could let it talk freely. But let us sum up briefly the essential difference which separates a dream from the waking state. In the dream the same faculties are exercised as during waking, but they are in a state of tension in the one case, and of relaxation in the other. The dream consists of the entire mental life minus the tension, the effort and the bodily movement. We perceive still, we remember still, we reason still. All this can abound in the dream; for abundance, in the domain of the mind, does not mean effort. What requires an effort is the precision of adjustment. To connect the sound of a barking dog with the memory of a crowd that murmurs and shouts requires no effort. But in order that this sound should be perceived as the barking of a dog, a positive effort must be made. It is this force that the dreamer lacks. It is by that, and by that alone, that he is distinguished from the waking man.

From this essential difference can be drawn a great many others. We can come to understand the chief characteristics of the dream. But I can only outline the scheme of this study. It depends especially upon three points, which are: the incoherence of dreams, the abolition of the sense of duration that often appears to be manifested in dreams, and, finally, the order in which the memories present themselves to the dreamer, contending for the sensations present where they are to be embodied.

The incoherence of the dream seems to me easy enough to explain. As it is characteristic of the dream not to demand a complete adjustment between the memory image and the sensation, but, on the contrary, to allow some play between them, very different memories can suit the same sensation. For example, there may be in the field of vision a green spot with white points. This might be a lawn spangled with white flowers. It might be a billiard-table with its balls. It might be a host of other things besides. These different memory images, all capable of utilizing the same sensation, chase after it. Sometimes they attain it, one after the other. And so the lawn becomes a billiard-table, and we watch these extraordinary transformations. Often it is at the same time, and altogether that these memory images join the sensation, and then the lawn will be a billiard-table. From this come those absurd dreams where an object remains as it is and at the same time becomes something else. As I have just said, the mind, confronted by these absurd visions, seeks an explanation and often thereby aggravates the incoherence.

As for the abolition of the sense of time in many of our dreams, that is another effect of the same cause. In a few seconds a dream can present to us a series of events which will occupy, in the waking state, entire days. You know the example cited by M. Maury: it has become classic, and although it has been contested of late, I regard it as probable, because of the great number of analogous observations that I found scattered through the literature of dreams. But this precipitation of the images is not at all mysterious. When we are awake we live a life in common with our fellows. Our attention to this external and social life is the great regulator of the succession of our internal states. It is like the balance wheel of a watch, which moderates and cuts into regular sections the undivided, almost instantaneous tension of the spring. It is this balance wheel which is lacking in the dream. Acceleration is no more than abundance a sign of force in the domain of the mind. It is, I repeat, the precision of adjustment that requires effort, and this is exactly what the dreamer lacks. He is no longer capable of that attention to life which is necessary in order that the inner may be regulated by the outer, and that the internal duration fit exactly into the general duration of things.

It remains now to explain how the peculiar relaxation of the mind in the dream accounts for the preference given by the dreamer to one memory image rather than others, equally capable of