pression made upon the waking life by the memory left from the dream in the morning, for in this memory the dream, as compared with the rest of the psychic content, seems something strange, coming, as it were, from another world. It would likewise be wrong to suppose that the theory of the supernatural origin of dreams lacks followers in our own day; for leaving out of consideration all bigoted and mystical authors—who are perfectly justified in adhering to the remnants of the once extensive realm of the supernatural until they have been swept away by scientific explanation—one meets even sagacious men averse to anything adventurous, who go so far as to base their religious belief in the existence and co-operation of superhuman forces on the inexplicableness of the dream manifestations (Haffner32). The validity ascribed to the dream life by some schools of philosophy, e.g. the school of Schelling, is a distinct echo of the undisputed divinity of dreams in antiquity, nor is discussion closed on the subject of the mantic or prophetic power of dreams. This is due to the fact that the attempted psychological explanations are too inadequate to overcome the accumulated material, however strongly all those who devote themselves to a scientific mode of thought may feel that such assertions should be repudiated. To write a history of our scientific knowledge of dream problems is so difficult because, however valuable some parts of this knowledge may have been, no progress in definite directions has been discernible. There has been no construction of a foundation of assured results upon which future investigators could continue to build, but every new author takes up the same problems afresh and from the very beginning. Were I to follow the authors in chronological order, and give a review of the opinions each has held concerning the problems of the dream, I should be prevented from drawing a clear and complete picture of the present state of knowledge on the subject. I have therefore preferred to base the treatment upon themes rather than upon the authors, and I shall cite for each problem of the dream the material found in the literature for its solution.
But as I have not succeeded in mastering the entire literature, which is widely disseminated and interwoven with