[Footnote 199: In most cases the missing memory, after making itself felt outside the conscious area, seems to reach that area, not so much by its own spontaneous unconscious movement as by a tentative search for clues. Thus I read one day the words 'the breaking of a goblet by a little black imp,' and immediately became conscious that I was reminded of something similar in recent experience, but could not tell what. I asked myself if it could have been in a dream. In a few moments, however, the memory recurred to me that two hours previously I had noticed a broken vase, and casually wondered how it had become broken. Under such circumstances we are for a time thinking of something, and yet have no conscious knowledge as to what we are thinking of.] [Footnote 200: Jastrow remarks, somewhat in the same way (_The Subconscious_, p. 93), that 'a letting down of the effort, a focusing of the mind upon a point a little or a good deal to one side of the fixation point, distinctly aids the mental vision.' The process seems, however, to be most effective when it is automatic, for attention cannot easily relax its own tension. A large number of the discoveries and solutions of difficulties effected in dreams are due to this dispersal of attention over a wider field, so enabling the missing relationship to be detected. See, for instance, some cases recorded by Newbold (_Psychological Review_, March 1896, p. 132), as of Dr. Hilprecht, the Assyriologist, who discovered in a dream that two fragments of tablets he had vainly been endeavouring to decipher, were really parts of the same tablet.] [Footnote 201: Hypermnesia, or excessive memory, is found in waking life in various abnormal conditions. It is not uncommon in men of genius; Macaulay is a well-known example. It scarcely seems, however, an especially favourable condition for keen intellectual power; the mental machine that is clogged with unnecessary and unimportant facts can scarcely fail to work under difficulties. 'Hypermnesia,' remarks Stoddart ('Early Symptoms of Mental Disease,' _British Medical Journal_, 11th May 1907), 'occurs most frequently in certain cases of idiocy, and in some cases of chronic mania. One such patient could enumerate all the occasions when any given medical officer had played tennis since he entered the institution.' Hypermnesia in dreams has been dealt with by Carl du Prel, _Philosophy of Mysticism_, vol. ii. ch. i.] [Footnote 202: This delay is worth mentioning, for it is conceivable that, in the case of a weak recollection, transference to the subconscious sphere of sleep might involve a temporary disappearance from the conscious waking sphere.]