_Reason in Dreams._--Studies of dreams of normal individuals based on large collections of instances are singularly few in number; such as there are indicate great variations in the source of dream thoughts and images, in the coherence of the dream, and in the powers of memory. In ordinary life attention dominates the images presented; in dreams heterogeneous and disconnected elements are often combined; a resemblance need not even have been consciously recognized for the mind to combine two impressions in a dream; for example, an aching tooth may (according to the dream) be extracted, and found to resemble rocks on the sea-shore, which had not struck the waking mind as in any way like teeth. Incongruence and incoherence are not, however, a necessary characteristic of dreams, and individuals are found whose dream ideas and scenes show a power of reasoning and orderliness equal to that of a scene imagined or experienced in ordinary life. In some cases the reasoning power may attain a higher level than that of the ordinary conscious life. In a well-authenticated case Professor Hilprecht was able in a dream to solve a difficulty connected with two Babylonian inscriptions, which had not previously been recognized as complementary to each other; a point of peculiar interest is the dramatic form in which the information came to him--an old Babylonian priest appeared in his dream and gave him the clue to the problem (see also below, Personality). _Memory in Dreams._--Although prima facie the dream memory is fragmentary and far less complete than the waking memory, it is by no means uncommon to find a revival in sleep of early, apparently quite forgotten, experiences: more striking is the recollection in dreams of matters never supraliminally (see SUBLIMINAL SELF) apperceived at all.