that your feet are not touching the earth. And, nevertheless, not believing yourself asleep, you have lost sight of the fact that you are lying down. Therefore, since you are not lying down and yet your feet do not feel the resistance of the ground, the conclusion is natural that you are floating in space. Notice this also: when levitation accompanies the flight, it is on one side only that you make an effort to fly. And if you woke at that moment you would find that this side is the one on which you are lying, and that the sensation of effort for flight coincides with the real sensation given you by the pressure of your body against the bed. This sensation of pressure, dissociated from its cause, becomes a pure and simple sensation of effort and, joined to the illusion of floating in space, is sufficient to produce the dream.

It is interesting to see that these sensations of pressure, mounting, so to speak, to the level of our visual field and taking advantage of the luminous dust which fills it, effect its transformation into forms and colors. M. Max Simon tells of having a strange and somewhat painful dream. He dreamt that he was confronted by two piles of golden coins, side by side and of unequal height, which for some reason or other he had to equalize. But he could not accomplish it. This produced a feeling of extreme anguish. This feeling, growing moment by moment, finally awakened him. He then perceived that one of his legs was caught by the folds of the bedclothes in such a way that his two feet were on different levels and it was impossible for him to bring them together. From this the sensation of inequality, making an irruption into the visual field and there encountering (such at least is the hypothesis which I propose) one or more yellow spots, expressed itself visually by the inequality of the two piles of gold pieces. There is, then, immanent in the tactile sensations during sleep, a tendency to visualize themselves and enter in this form into the dream.

More important still than the tactile sensations, properly speaking, are the sensations which pertain to what is sometimes called internal touch, deep-seated sensations emanating from all points of the organism and, more particularly, from the viscera. One cannot imagine the degree of sharpness, of acuity, which may be obtained during sleep by these interior sensations. They doubtless already exist as well during waking. But we are then distracted by practical action. We live outside of ourselves. But sleep makes us retire into ourselves. It happens frequently that persons subject to laryngitis, amygdalitis, etc., dream that they are attacked by their affection and experience a disagreeable tingling on the side of their throat. When awakened, they feel nothing more, and believe it an illusion; but a few hours later the illusion becomes a reality. There are cited maladies and grave accidents, attacks of epilepsy, cardiac affections, etc., which have been foreseen and, as it were, prophesied in dreams. We need not be astonished, then, that philosophers like Schopenhauer have seen in the dream a reverberation, in the heart of consciousness, of perturbations emanating from the sympathetic nervous system; and that psychologists like Schemer have attributed to each of our organs the power of provoking a well-determined kind of dream which represents it, as it were, symbolically; and finally that physicians like Artigues have written treatises on the semeiological value of dreams, that is to say, the method of making use of dreams for the diagnosis of certain maladies. More recently, M. Tissié, of whom we have just spoken, has shown how specific dreams are connected with affections of the digestive, respiratory, and circulatory apparatus.

I will summarize what I have just been saying. When we are sleeping naturally, it is not necessary to believe, as has often been supposed, that our senses are closed to external sensations. Our senses continue to be active. They act, it is true, with less precision, but in compensation they embrace a host of "subjective" impressions which pass unperceived when we are awake—for then we live in a world of perceptions common to all men—and which reappear in sleep, when we live only for ourselves. Thus our faculty of sense perception, far from being narrowed during sleep at all points, is on the contrary extended, at least in certain directions, in its field of operations. It is true that it often loses in energy, in tension, what it gains in extension. It brings to us only confused impressions. These impressions are the materials of our dreams. But they are only the materials, they do not suffice to produce them.

They do not suffice to produce them, because they are vague and indeterminate. To speak only of those that play the principal rôle, the changing colors and forms, which deploy before us when our eyes are closed, never have well-defined contours. Here are black lines upon a white background. They may represent to the dreamer the page of a book, or the facade of a new house with dark blinds, or any number of other things. Who will choose? What is the form that will imprint its decision upon the indecision of this material? This form is our memory.

Let us note first that the dream in general creates nothing. Doubtless there may be cited some examples of artistic, literary and scientific production in dreams. I will recall only the well-known anecdote told of Tartini, a violinist-composer of the eighteenth century. As he was trying to compose a sonata and the muse remained recalcitrant, he went to sleep and he saw in a dream the devil, who seized his violin and played with master hand the desired sonata. Tartini wrote it out from memory when he woke. It has come to us under the name of "The Devil's Sonata." But it is very difficult, in regard to such old cases, to distinguish between history and legend. We should have auto-observations of certain authenticity. Now I have not been able to find anything more than that of the contemporary English novelist, Stevenson. In a very curious essay entitled "A Chapter on Dreams," this author, who is endowed with a rare talent for analysis, explains to us how the most original of his stories have been composed or at least sketched in dreams. But read the chapter carefully. You will see that at a certain time in his life Stevenson had come to be in an habitual psychical state where it was very hard for him to say whether he was sleeping or waking. That appears to me to be the truth. When the mind creates, I would say when it is capable of giving the effort of organization and synthesis which is necessary to triumph over a certain difficulty, to solve a problem, to produce a living work of the imagination, we are not really asleep, or at least that part of ourselves which labors is not the same as that which sleeps. We cannot say, then, that it is a dream. In sleep, properly speaking, in sleep which absorbs our whole personality, it is memories and only memories which weave the web of our dreams. But often we do not recognize them. They may be very old memories, forgotten during waking hours, drawn from the most obscure depths of our past; they may be, often are, memories of objects that we have perceived distractedly, almost unconsciously, while awake. Or they may be fragments of broken memories which have been picked up here and there and mingled by chance, composing an incoherent and unrecognizable whole. Before these bizarre assemblages of images which present no plausible significance, our intelligence (which is far from surrendering the reasoning faculty during sleep, as has been asserted) seeks an explanation, tries to fill the