murder, and finally he himself was summoned before the Tribunal. There he saw Robespierre, Marat, Fouquier-Tinville, and all the sorry heroes of those terrible days; he had to give an account of himself, and after all manner of incidents which did not fix themselves in his memory, he was sentenced to death. Accompanied by an enormous crowd, he was led to the place of execution. He mounted the scaffold; the executioner tied him to the plank, it tipped over, and the knife of the guillotine fell. He felt his head severed from his trunk, and awakened in terrible anxiety, only to find that the head-board of the bed had fallen, and had actually struck the cervical vertebrae just where the knife of the guillotine would have fallen.

This dream gave rise to an interesting discussion, initiated by Le Lorrain and Egger in the Revue Philosophique, as to whether, and how, it was possible for the dreamer to crowd together an amount of dream-content apparently so large in the short space of time elapsing between the perception of the waking stimulus and the moment of actual waking.

Examples of this nature show that objective stimuli occurring in sleep are among the most firmly-established of all the sources of dreams; they are, indeed, the only stimuli of which the layman knows anything whatever. If we ask an educated person who is not familiar with the literature of dreams how dreams originate, he is certain to reply by a reference to a case known to him in which a dream has been explained after waking by a recognized objective stimulus. Science, however, cannot stop here, but is incited to further investigation by the observation that the stimulus influencing the senses during sleep does not appear in the dream at all in its true form, but is replaced by some other representation, which is in some way related to it. But the relation existing between the stimulus and the resulting dream is, according to Maury, "une affinite quelconque mais qui n'est pas unique et exclusive" * (p. 72). If we read, for example, three of Hildebrandt's "alarm-clock dreams," we shall be compelled to ask why the same casual stimulus evoked so many different results, and why just these results and no others.

* A sort of relation which is, however, neither unique nor exclusive.

(p. 37): "I am taking a walk on a beautiful spring morning. I stroll through the green meadows to a neighbouring village, where I see numbers of the inhabitants going to church, wearing their best clothes and carrying their hymn-books under their arms. I remember that it is Sunday, and that the morning service will soon begin. I decide to attend it, but as I am rather overheated I think I will wait in the churchyard until I am cooler. While reading the various epitaphs, I hear the sexton climbing the church- tower, and I see above me the

small bell which is about to ring for the beginning of service. For a little while it hangs motionless; then it begins to swing, and suddenly its notes resound so clearly and penetratingly that my sleep comes to an end. But the notes of the bell come from the alarm-clock."

"A second combination. It is a bright winter day; the streets are deep in snow. I have promised to go on a sleigh-ride, but I have to wait some time before I am told that the sleigh is at the door. Now I am preparing to get into the sleigh. I put on my furs, the foot-warmer is put in, and at last I have taken my seat. But still my departure is delayed. At last the reins are twitched, the horses start, and the sleigh bells, now violently shaken, strike up their familiar music with a force that instantly tears the gossamer of my dream. Again it is only the shrill note of my alarm- clock."

"Yet a third example. I see the kitchen-maid walking along the passage to the dining-room, with a pile of several dozen plates. The porcelain column in her arms seems to me to be in danger of losing its equilibrium. 'Take care,' I exclaim, 'you will drop the whole pile!' The usual retort is naturally made- that she is used to such things, etc. Meanwhile I continue to follow her with my anxious gaze, and behold, at the threshold the fragile plates fall and crash and roll across the floor in hundreds of pieces. But I soon perceive that the endless din is not really a rattling but a true ringing, and with this ringing the dreamer now becomes aware that the alarm-clock has done its duty."

The question why the dreaming mind misjudges the nature of the objective sensory stimulus has been answered by Strumpell, and in an almost identical fashion by Wundt; their explanation is that the reaction