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 lacunae. It fills them by calling up other memories which, presenting themselves often with the same deformations and the same incoherences as the preceding, demand in their turn a new explanation, and so on indefinitely. But I do not insist upon this point for the moment. It is sufficient for me to say, in order to answer the question which I have propounded, that the formative power of the materials furnished to the dream by the different senses, the power which converts into precise, determined objects the vague and indistinct sensations that the dreamer receives from his eyes, his ears, and the whole surface and interior of his body, is the memory.