that concerns the true nature of the dream or that solves definitively any of its enigmas. Still less of course has been transmitted to the knowledge of the educated laity.
The first book in which the dream is treated as an object of psychology seems to be that of Aristotle (Concerning Dreams and their Interpretation). Aristotle asserts that the dream is of demoniacal, though not of divine nature, which indeed contains deep meaning, if it be correctly interpreted. He was also acquainted with some of the characteristics of dream life, e.g., he knew that the dream turns slight sensations perceived during sleep into great ones ("one imagines that one walks through fire and feels hot, if this or that part of the body becomes slightly warmed"), which led him to conclude that dreams might easily betray to the physician the first indications of an incipient change in the body passing unnoticed during the day. I have been unable to go more deeply into the Aristotelian treatise, because of insufficient preparation and lack of skilled assistance.
As every one knows, the ancients before Aristotle did not consider the dream a product of the dreaming mind, but a divine inspiration, and in ancient times the two antagonistic streams, which one finds throughout in the estimates of dream life, were already noticeable. They distinguished between true and valuable dreams, sent to the dreamer to warn him or to foretell the future, and vain, fraudulent, and empty dreams, the object of which was to misguide or lead him to destruction. This pre-scientific conception of the dream among the ancients was certainly in perfect keeping with their general view of life, which was wont to project as reality in the outer world that which possessed reality only within the mind. It, moreover, accounted for the main im-
- Compare, on the other hand, O. Gruppe, Griechische Mythologie und Religionsgeschichte, p. 390. "Dreams were divided into two classes; the first were influenced only by the present (or past), and were unimportant for the future: they embraced the ένύπνια, insomnia, which immediately produces the given idea or its opposite, e.g. hunger or its satiation, and the φαντάσματα, which elaborates the given idea phantastically, as e.g. the nightmare, ephialtes. The second class was, on the other hand, determinant for the future. To this belong: (1) direct prophecies received in the dream (χρηματωμδς, oraculum); (2) the foretelling of a future event (ὅραμα); (3) the symbolic or the dream requiring interpretation (ὅνειρος, somnium). This theory has been preserved for many centuries."