In attempting to unravel these, it is probable that, as in explaining the illusion of rapidity, we must always bear in mind the tendency of memory-groups in dreams to fall apart from their waking links of association, so well as the complementary tendency to form associations which in waking life would only be attained by a strained effort. Apperception, with the power it involves of combining and bringing to a focus all the various groups of memories bearing on the point in hand, is defective. The focus of conscious attention is contracted, and there is the curious and significant phenomenon that sleeping consciousness is occasionally unconscious of psychic elements which yet are present just outside it and thrusting imagery into its focus. The imagery becomes conscious, but its relation to the existing focus of consciousness is not consciously perceived. Such a psychic mechanism, as Freud and his disciples have shown, quite commonly appears in hysteria and obsessional neuroses when healthy normal consciousness is degraded to a pathological level resembling that which is normal in dreams.[195] In such a case the surface of sleeping consciousness is, as it were, crumpled up, and the concealed portion appears only at the end of the dream or not at all. A simple example may make this clear. In a dream I ask a lady if she knows the work of the poet Bau; she replies that she does not; then I see before me a paper having on it the name Baudelaire, clearly the name which should have been contained in my query.[196] In such a dream the crumpling and breaking of consciousness, at its very focus, is shown in the most unmistakable manner.[197] But many of the most remarkable dreams of dramatic dreamers are due to the same phenomenon, which in an intellectual form is exactly the phenomenon which always makes a dramatic situation effective. Robert Louis Stevenson was an abnormally vivid dreamer, and found the germ of some of the plots of his stories in his dreams; he has described one of his dreams in which the dreamer imagines he has committed a murder; the crime becomes known to a woman who, however, never denounces it; the murderer lives in terror, and cannot conceive why the woman prolongs his torture by this delay in giving him up to justice; only at the end of the dream comes the clue to the mystery, and the explanation of the woman's attitude, as she falls on her knees and cries: 'Do you not understand? I love you.'[198]

There is another and very interesting class of dreams in which we find not merely that some memory-groups disappear from consciousness or become merely latent, but also that other memory-groups, latent or even lost to waking consciousness, float into the focus of sleeping consciousness. In other words, we can remember in sleep what we have forgotten awake. We then have what is called the hypermnesia, the excessive or abnormal memory, of sleep.

There can be little doubt that the two processes—the sinking of some memory-groups and the emergence on the surface of other memory-groups which, so far as waking life is concerned, had apparently fallen to the depths and been drowned—are complementarily related to one another. We remember what we have forgotten because we forget what we remembered. The order of our waking impressions involves a certain tension, that is to say a certain attention, which holds them in our consciousness, and excludes any other order which might serve to bring lost memory-groups to sight. Sometimes we are conscious of a lost memory which is just outside consciousness, but which, with the existing order of our memory-groups, we cannot bring into consciousness. We have the missing name, the missing memory, at the tip of our tongue, we say, but we cannot quite catch it.[199] In dreams apperception is defective, the strain of conscious attention is relaxed, and the conditions are furnished under which new clues and strains may come into action and the missing name glide spontaneously into consciousness. Even the mere approach of sleep, with its accompanying relaxation of attention, may effect this end. Thus I was trying one day to recall the name of the unpleasant Chinese scent, patchouli. The name, though not usually unfamiliar, escaped me. At night, however, just before falling asleep, it spontaneously occurred to me. In the morning, when fully awake, I was again unable to recall it.

In such a case we see how waking consciousness is tense in a certain direction, which happens not to be that in which the desired thing is to be found. Attention under such circumstances impedes rather than aids recollection. In this particular case, I felt convinced that the name I wanted began with h, and thus my mind was intently directed towards a wrong quarter. But on the approach of sleep attention is automatically relaxed, and it is then possible for the forgotten word to slip in from its unexpected quarter. On these occasions it is by indirection that direction is found.[200]

It is interesting to observe that this same process of discovery due to the wider outlook of relaxed attention can take place, not only in sleep and the hypnagogic state, but also, subconsciously, in the fully waking state when the mind is occupied with some other subject. Thus in reading a MS., I came upon an illegible word which I was unable to identify, notwithstanding several guesses and careful scrutiny through a magnifying glass. I passed on, dismissing the subject from my mind. A quarter of an hour afterwards, when walking, and thinking of quite a different subject, I became conscious that the word 'ceremonial' had floated into the field of mental vision, and I at once realised that this was the unidentified word. The instance may be trivial, but no example could better show how the mind may continue to work subconsciously in one direction while consciously working in an entirely different direction.

In dreams, however, we can effect more than a mere recovery of memories which have temporarily escaped us, or the discovery of relationships which have eluded us. The dissociation of familiar memory-groups becomes so complete, the appearance of unfamiliar groups so eruptive, that we can remember things that have entirely and permanently sunk below the surface of waking consciousness, or even things which are so insignificant that they have never made any mark on waking consciousness at all. In this way, we may be said, in a certain sense, to remember things we never knew. The first dream which enabled me, some twenty years ago, to realise this hypermnesia of the mind in dreams[201] was the following unimportant but instructive case. I woke up recalling the chief items of a rather vivid dream: I had imagined myself in a large old house, where the furniture, though of good quality, was ancient, and the chairs threatened to give way as one sat on them. The place belonged to one Sir Peter Bryan, a hale old gentleman, who was accompanied by his son and grandson. There was a question of my buying the place from him, and I was very complimentary to the old gentleman's appearance of youthfulness, absurdly affecting not to know which was the grandfather and which the grandson. On awaking I said to myself that here was a purely imaginative dream, quite unsuggested by any definite experiences. But when I began to recall the trifling incidents of the previous day, and the things I had seen and read, I realised that that was far from being the case. So far from the dream having been a pure effort of imagination, I found that every minute item could be traced to some separate source, though none of them had the slightest resemblance to the dream as a whole. The name of Sir Peter Bryan alone completely baffled me; I could not even recall that I had at that time ever heard of any one called Bryan. I abandoned the search and made my notes of the dream and its sources. I had scarcely done so when I chanced to take up a volume of biographies of eccentric personages, which I had glanced through carelessly the day before. I found that it contained, among others, the lives of Lord Peterborough and George Bryan Brummel. I had certainly seen those names the day before; yet before I took up the book once again it would have been impossible for me to recall the exact name of Beau Brummel. It so happened that the forgotten memory which in this case re-emerged to sleeping consciousness, was a fact of no consequence to myself or any one else. But it furnishes the key to many dreams which have been of more serious import to the dreamers.

Since then I have been able to observe among my friends several instances of dreams containing veracious though often trivial circumstances unknown to the dreamer when awake, though on consideration it was found to be in the highest degree probable that they had come under his notice, and been forgotten, or not consciously observed. Thus a musical correspondent tells me he once dreamed of playing a piece of Rubinstein's in the presence of a friend who told him he had made a mistake in re-striking a tied note. In the morning he found the dream friend was correct. But up to then he had always repeated the note. Usually when the forgotten or unnoticed circumstance is trivial, it is of quite recent date. That it is not always very recent may be illustrated by a dream of my own. I dreamed that I was in Spain and about to rejoin some friends at a place which was called, I thought, Daraus, but on reaching the booking-office I could not remember whether the place I wanted to go to was called Daraus, Varaus, or Zaraus, all which places, it seemed to me, really existed. On awaking, I made a note of the dream, exactly as reproduced here, but was unable to recall any place, in Spain or elsewhere, corresponding to any of these names. The dream seemed merely to illustrate the familiar way in which a dream image perpetually shifts in a meaningless fashion at the focus of sleeping consciousness. The note was put away, and a few months later taken out again.[202] It was still equally impossible to me to recall any real name corresponding to the dream names. But on consulting the Spanish guide-books and railway time-tables, I found that, on the line between San Sebastian and Bilbao, there really is a little seaside resort, in a beautiful situation, called Zarauz, and I realised, moreover, that I had actually passed that station in the train two hundred and fifty days before the date of my dream.[203] I had no associations with this place, though I may have admired it at the time; in any case it vanished permanently from conscious memory, perhaps aided by the fatigue of a long night journey before entering Spain. Even sleeping memory, I may remark, only recovered it with an effort, for it is notable that the name was gradually approached by three successive attempts.[204]

A special form of lost or unconscious memories recurring in sleep is constituted by the cases in which people when asleep, or in a somnambulistic state, can speak languages which they have forgotten, or never consciously known, when awake. A simple instance, known to me, is furnished by a servant who had been taken to Paris for a few weeks six months before, but had never learned to speak a word of French, and whose mistress overheard her talking in her sleep, and repeating various French phrases, like 'Je ne sais pas, Monsieur'; she had certainly heard these phrases, though she maintained, when awake, that she was ignorant of them. Speaking in a language not consciously known, or xenoglossia, as it is now termed, occurs under various abnormal conditions, as well as in sleep, and is sometimes classed with the tendency which is found, especially under great religious excitement, to 'speak with tongues,' or to utter gibberish.[205] But in various sleep-like states it occurs as a true revival of forgotten memories, sometimes of memories which belong to childhood and in normal consciousness have been long overlaid and lost. On one occasion, by the bedside of a lady who was kept for a considerable period in a light condition of chloroform anaesthesia, the patient began to talk in an unfamiliar language which one of us recognised as Welsh; as a child, she afterwards owned, she had known Welsh, but had long since forgotten it.[206] A similar reproduction of lost memories occurs in the hypnotic state.

This psychic process, by which unconscious memories become conscious in dreams, is of considerable interest and importance because it lends itself to many delusions. Not only the ignorant and uncultured, but even well-trained and acute minds, are often so unskilled in mental analysis that they are quite unable to pierce beneath the phenomenon of conscious ignorance to the deeper fact of unconscious memory; they are completely baffled, or else they resort to the wildest hypotheses. This is illustrated by the following narrative received twelve years ago from a medical correspondent in Baltimore. 'Several years ago,' he writes, 'a friend made a social call at my house and in the course of conversation spoke very enthusiastically of Mascagni's Cavalleria Rusticana, the first performance of which in the United States he had attended a few nights previously. I had never even heard of the opera before, but that night I dreamed that I heard it performed. The dream was a very vivid one, so vivid that several times during the next day I found myself humming airs from the dream opera. Several evenings later I went to the theatre to see a comedy, and before the curtain rose the orchestra played a selection which I instantly recognised as part of my dream opera. I exclaimed to a lady who was with me: "That selection is from Cavalleria Rusticana." On inquiring of the leader of the orchestra such proved to be the case.' Now, at that period, shortly after the first appearance of Cavalleria Rusticana, portions of it had become extremely popular and were heard everywhere, by no means merely on the operatic stage. It was difficult not to have heard something of it. There cannot be the slightest doubt that my correspondent had heard not only the name but the music, though, writing at an interval of some years, he probably exaggerated the extent of his unconscious recollections. This seems the simple explanation of what to my correspondent was an inexplicable mystery. Other people, like the late Frederick Greenwood, not content to remain baffled, go further and regard such dreams as 'dreams of revelation,' as they also consider that class of dreams in which the dreamer works out the solution of a difficulty which he had vainly grappled with when awake.