The third, most remarkable, and at the same time most incomprehensible, peculiarity of memory in dreams is shown in the selection of the material reproduced; for here it is not, as in the waking state, only the most significant things that are held to be worth remembering, but also the most indifferent and insignificant details. In this connection I will quote those authors who have expressed their surprise in the most emphatic language.

Hildebrandt (p. 11): "For it is a remarkable fact that dreams do not, as a rule, take their elements from important and far-reaching events, or from the intense and urgent interests of the preceding day, but from unimportant incidents, from the worthless odds and ends of recent experience or of the remoter past. The most shocking death in our family, the impressions of which keep us awake long into the night, is obliterated from our memories until the first moment of waking brings it back to us with distressing force. On the other hand, the wart on the forehead of a passing stranger, to whom we did not give a moment's thought once he was out of sight, finds a place in our dreams."

Strumpell (p. 39) speaks of "cases in which the analysis of a dream brings to light elements which, although derived from the experiences of yesterday or the day before yesterday, were yet so unimportant and worthless for the waking state that they were forgotten soon after they were experienced. Some experiences may be the chance-heard remarks of other persons, or their superficially observed actions, or, fleeting perceptions of things or persons, or isolated phrases that we have read, etc."

Havelock Ellis (p. 727): "The profound emotions of waking life, the questions and problems on which we spend our chief voluntary mental energy, are not those which usually present themselves at once to dream- consciousness. It is, so far as the immediate past is concerned, mostly the trifling, the incidental, the 'forgotten' impressions of daily life which reappear in our dreams. The psychic activities that are awake most intensely are those that sleep most profoundly."

It is precisely in connection with these characteristics of memory in dreams that Binz (p. 45) finds occasion to express dissatisfaction with the explanations of dreams which he himself had favoured: "And the normal dream raises similar questions. Why do we not always dream of mental impressions of the day before, instead of going back, without any perceptible reason, to the almost forgotten past, now lying far behind us? Why, in a dream, does consciousness so often revive the impression of indifferent memory- pictures, while the cerebral cells that bear the most sensitive records of experience remain for the most part inert and numb, unless an acute revival during the waking state has quite recently excited them?"

We can readily understand how the strange preference shown by the dream- memory for the indifferent and therefore disregarded details of daily experience must commonly lead us altogether to overlook the dependence of dreams on the waking state, or must at least make it difficult for us to prove this dependence in any individual case. Thus it happened that in the statistical treatment of her own and her friend's dream, Miss Whiton Calkins found that 11 per cent of the entire number showed no relation to the waking state. Hildebrandt was certainly correct in his assertion that all our dream-images could be genetically explained if we devoted enough time and material to the tracing of their origin. To be sure, he calls this "a most tedious and thankless job. For most often it would lead us to ferret out all sorts of psychically worthless things from the remotest corners of our storehouse of memories, and to bring to light all sorts of quite indifferent events of long ago from the oblivion which may have overtaken them an hour after their occurrence." I must, however, express my regret that this discerning author refrained from following the path which at first sight seemed so unpromising, for it would have led him directly to the central point of the explanation of dreams.

The behaviour of memory in dreams is surely most significant for any theory of memory whatsoever. It teaches us that "nothing which we have once psychically possessed is ever entirely lost" (Scholz, p. 34); or as Delboeuf puts it, "que toute impression, meme la plus insignificante, laisse une trace inalterable, indifiniment susceptible de reparaitre au jour"; * a conclusion to which we are urged by so many other pathological manifestations of mental life. Let us bear in mind this extraordinary capacity of the memory in dreams, in order the more keenly to realize the contradiction which has to be put forward in certain