I have spoken of visual sensations. They are the principal ones. But the auditory sensations nevertheless play a role. First, the ear has also its internal sensations, sensations of buzzing, of tinkling, of whistling, difficult to isolate and to perceive while awake, but which are clearly distinguished in sleep. Besides that we continue, when once asleep, to hear external sounds. The creaking of furniture, the crackling of the fire, the rain beating against the window, the wind playing its chromatic scale in the chimney, such are the sounds which come to the ear of the sleeper and which the dream converts, according to circumstances, into conversation, singing, cries, music, etc. Scissors were struck against the tongs in the ears of Alfred Maury while he slept. Immediately he dreamt that he heard the tocsin and took part in the events of June, 1848. Such observations and experiences are numerous. But let us hasten to say that sounds do not play in our dreams so important a role as colors. Our dreams are, above all, visual, and even more visual than we think. To whom has it not happened--as M. Max Simon has remarked--to talk in a dream with a certain person, to dream a whole conversation, and then, all of a sudden, a singular phenomenon strikes the attention of the dreamer. He perceives that he does not speak, that he has not spoken, that his interlocutor has not uttered a single word, that it was a simple exchange of thought between them, a very clear conversation, in which, nevertheless, nothing has been heard. The phenomenon is easily enough explained. It is in general necessary for us to hear sounds in a dream. From nothing we can make nothing. And when we are not provided with sonorous material, a dream would find it hard to manufacture sonority.