The bladder, again, is an internal organ which makes its functional needs felt only at intervals, and thus, when those needs occur during sleep, they become conscious in imagery which easily recalls the source of the stimulus. It may, indeed, be said that vesical dreams are full of instruction in the light they throw on the psychology of dreaming. This has long been well known to writers on dreams. Thus Scherner, many years ago, insisted on the interest and importance of vesical dreams. In women, especially, he regarded them as very frequent and developed, most dream stories of women, he considered, containing symbolic representations of this organic irritation. Water, in some form or another, is naturally the commonestsymbol. In Scherner's opinion, also, all dreams of fish playing in the water are vesical dreams.[69]
In its simplest form the vesical dream is what Freud would term a wish-dream of infantile type, frequently in the magnified form common in dreams, and sometimes transferred from the dreamer himself to become objectified in another person, or even an inanimate object.[70]There is, however, a very important difference according to whether these dreams take place in an adult or in a young child. In the adult it almost invariably happens that the dream act remains merely a dream act, and no corresponding motor impulse is transmitted to the bladder. But when such dreams occur to very young children, in whose brains the motor inhibitory mechanism is not yet fully established, it not infrequently happens that the motor impulse is transmitted and the expulsive action of the bladder is set up in sympathy with the imagery of the dream; thus is established the condition known as nocturnal enuresis. As the young brain develops, and inhibition becomes more perfect, these vesical dreams cease to exert any actual effect on the bladder, even when, as sometimes happens, they continue to occur at intervalsin adult life.[71]Occasionally, both in those who have and those who have not suffered from nocturnal enuresis in childhood (especially women), vesical dreams of this character may occur without even any real distension of the bladder. In some of these cases the dream can be shown to be due to a reminiscence or suggestion from the waking life of the previous day. Dreams stimulated by organic sensations from within are thus found to resemble those proceeding from sensory sensations from without in that they are both exactly simulated by dreams which are mainly of central origin.
When we turn to those internal organs of the body which normally carry on their functions in a constant and equable manner, seldom or never obtruding themselves into the sphere of consciousness, any disturbance of function seems much less likely to be translated into dream consciousness in a simple and direct form. It is sufficient to take the example of the heart. When the heart is acting normally any consciousness of its action is as rare asleep as awake. Even when cardiac action is disturbed, either by disease or by temporary excitement, dream consciousness seldom realises the physical cause of the disturbance. Occasionally, indeed, the cardiac disturbance may reach sleeping consciousness without any very remote transformation;thus a lady dreams that she is fainting while really breathing in a slightly laboured and spasmodic way; but at another period the same lady, at a time when she was suffering from some degree of heart weakness, dreamed one night, when the trouble was specially marked, that she was driving sweating horses up a steep hill, urging them on with the whip in order to avoid an express train which she imagined was behind her. This dream of sweating and panting horses climbing a hill has been noted by various observers to occur in connection with heart trouble.[72]The real difficulty of the panting and struggling heart instinctively finds its apparent explanation in a familiar spectacle of daily life.
In another case a dreamer awoke from a disturbed sleep associated with indigestion, having the impression that burglars were tramping upstairs, but immediately realised that the tramp of the burglars' feet was really the beating of her own heart. Somewhat similarly, when suffering from headache, I have dreamed of hammering nails into a floor, a theory obviously invented to account for the thump of throbbing arteries.
An interesting group of phenomena connected with the sensory influences discussed in this chapter is furnished by the premonitions of physical disorders and diseases sometimes experienced in dreams. A physical disturbance may reach sleeping consciousness many hours, or even days, before it is perceived bywaking consciousness, and become translated into a more or less fantastic dream. This has been recognised from of old, and Aristotle, for instance, observed that dreams magnify sensory excitations, and pointed out that they were thus useful to the physician in diagnosing symptoms not yet perceptible in the waking state. Thus Hammond knew a gentleman who, before an attack of hemiplegic paralysis, repeatedly dreamed that he had been cut in two down the middle line, and could only move on one side, while a young lady who dreamed she had swallowed molten lead, though quite well on awaking, was attacked by severe tonsilitis toward midday. Erythematous conditions of the skin, as has been pointed out to me by Dr. Kiernan, who has met with numerous cases in point, play an especial part in generating these dreams. Jewell, again, mentions a girl who dreamed, three days before being laid up with typhoid fever, that some one threw oil over her and set light to it. Macario, who was, perhaps, the first to record and study scientifically the dreams of this class, termed them prodromic.[73]
'Prophetic' dreams, in which the dreamer foresees, not a physical condition which is already latent, but an external occurrence, belong to an entirely differentclass, and need not be discussed in detail here, since they are usually fallacious. A fairly common experience of this kind is the dream of an unknown person who is afterwards met in real life. These dreams fall into two groups: in the first the 'prophecy' is based on a failure of memory, the dreamer having really seen the person before; in the second, the subsequent 'recognition' of the person is due to the emotional preparation of the dream, and the concentrated expectation. Sante de Sanctis, who points this out, gives an experience of the kind which happened to the distinguished novelist, Capuana, who had a vivid dream of a dark lady, with expressive eyes, and three days after met the lady of his dream in the street.[74]Women, in a state of emotional expectation, have often mistaken dead (or even living) persons for missing husbands or children, and any one who has observed how, when a noted criminal flies from justice, he is soon 'recognised,' from his portrait, in the most various parts of the world, will have no difficulty in believing that it is easily possible to 'recognise' people from dream portraits, which are much vaguer than photographs. That there are other prophetic dreams, less easy to account for, I am ready to admit, though they have not come under my own immediate observation.
EMOTION IN DREAMS
Emotion and Imagination—How Stimuli are transformed into Emotion—Somnambulism—The Failure of Movement in Dreams—Nightmare—Influence of the approach of Awakening on imagined Dream Movements—The Magnification of Imagery—Peripheral and Cerebral Conditions combine to produce this Imaginative Heightening—Emotion in Sleep also Heightened—Dreams formed to explain Heightened Emotions of unknown origin—The fundamental Place of Emotion in Dreams—Visceral and especially Gastric disturbance as a source of Emotion—Symbolism in Dreams—The Dreamer's Moral Attitude—Why Murder so often takes place in Dreams—Moral Feeling not Abolished in Dreams though sometimes Impaired.
Emotion and Imagination—How Stimuli are transformed into Emotion—Somnambulism—The Failure of Movement in Dreams—Nightmare—Influence of the approach of Awakening on imagined Dream Movements—The Magnification of Imagery—Peripheral and Cerebral Conditions combine to produce this Imaginative Heightening—Emotion in Sleep also Heightened—Dreams formed to explain Heightened Emotions of unknown origin—The fundamental Place of Emotion in Dreams—Visceral and especially Gastric disturbance as a source of Emotion—Symbolism in Dreams—The Dreamer's Moral Attitude—Why Murder so often takes place in Dreams—Moral Feeling not Abolished in Dreams though sometimes Impaired.
Whether the influences which stimulate our dreams arise from without or from within the organism, they are always filtered and diffused through the obscured channels of perception. They reach the brain at last in a vague and massive shape which may or may not betray to waking analysis the source from which they arise, but will certainly have become so changed in these organic channels that their affective tone will be predominant. They are, that is to say, largely transformed intoemotion. And, when so transformed, they become the origin of what we regard as the imaginative element in dreams.[75]
Sleep is especially favourable to the production of emotion because while it allows a considerable amount of activity to sensory activities, and a very wide freedom to the imagery founded on sensory activities, it largely and in many directions inhibits motor activity. The actions suggested by sensory excitation cannot, therefore, be carried out. As soon as the impulse enters motor channels it is impeded, broken up, and scattered in a vain struggle. This process is transmitted to the brain as a wave of emotion.
Sometimes, indeed, as we know, motor co-ordinations, usually inhibited in sleep, are not so inhibited. The dreamer is able to execute, perfectly or imperfectly, some action which, really or in imagination, he desires to execute. He is then said to be in a state of somnambulism. The somnambulist, in the wide sense of the word, is not necessarily a person who walks in his sleep, but any person in whom a group of co-ordinated muscles is sufficiently awake to respond more or less adequately to the motor impulse from the sleeping brain. To talk in sleep is a form of somnambulism. When the motor channels are thus unimpeded, there is usually no memory of a dream on awaking. The impulses that reach consciousness can be, as it were, quickly and easily drained off to the surface of the nervous system, and they tend to leave no deep impress on consciousness.
'I worked late last night,' writes a lady, a novelist, 'went to bed, and dropped into a dead kind of sleep. When I woke this morning about seven a funny thinghad happened. Two candles were burning in my room. When I went to bed I had only one burning, and I know I put that out. Now, there were two burning side by side as if I had been writing, and they had evidently been burning only an hour or so, I must have got up and lighted them in my sleep.'[76]The actions carried out in the somnambulistic condition are not usually co-ordinated with the action of higher emotions: thus, a young woman was impelled by a distended bladder, while still asleep, to get out of bed and proceeded to carry out the suggested action, but without further precautions, on to the floor; she was only awakened by an exclamation from her sister, who had been aroused by the sound. We seem to see that under a strong stimulus—unfinished work in one case, vesical tension in the other—the motor centres have awakened to activity in the early morning while the higher centres are still soundly asleep. If the second sleeper had not been awakened, in neither case would any memory of the incidents have remained.[77]There has been no struggle, and no resultant emotions have, therefore, been aroused to impress consciousness. It is evident that the lack of adaptation between sensory and motor activity is animportant factor in dreams, and contributes to impart to them their emotional character.
In somnambulism we have a state which is in some respects the reverse of that usual in dreams. The higher centres are, indeed, split off from the lower centres, but it is the former that are asleep and the latter are awake, whereas in ordinary dreaming the higher centres are acting in accordance with their means, while the lower centres are quiescent. Somnambulism is an approximation to a condition found in some diseases of the brain when, as a result of lesion of the higher nervous levels, we have a mental state—the ideatory apraxia of Liepmann—in which the muscular system carries out plans, but the plans are defective because not supervised by the higher centres. In ordinary dreams, on the other hand, we have a state comparable to that produced by brain lesions in what Pick terms motor apraxia, in which the higher centres are acting freely, but their plans are never carried into action owing to failure of the motor centres.
This characteristic of dreaming has seemed puzzling to some writers. They ask why, in our dreams, we should sometimes be so conscious of failure of movement, and why, when we strive to move in dreams, we do not always actually move.[78]
There scarcely seems to me to be any serious difficulty here; still, the question is one of considerable interest and importance. It is necessary to point out in the first place that, however complete the actual absence of movement, there is usually no failure of movement in the dream vision. We dream that we are talking, that we are moving from place to place, that we are performing various actions. We are conscious of no difficulty, even sometimes of a peculiar facility, in executing these movements. And in normal persons, under normal conditions, it would seem that the dream movements take place without even an incipient degree of corresponding actual movement perceptible to an observer. The efferent motor channels, and even to a large extent the afferent sensory channels, are asleep, and the whole representative circuit is completed within the brain, or, as we say, imaginatively.[79]Thus a middle-aged friend, whose habits are by no means athletic, dreams that, desiring to attract some one'sattention, he rests one knee on his wife's small work-table, and holding the foot of the other leg in one hand, he whirls rapidly and easily round and round on the pivot of the knee which rests on the table, the dream afterwards continuing without any awakening. A lady, again, who, when awake, is unable to swim, and knows no reason why she should think of swimming, vividly dreams that she jumps from a houseboat into the river, and proceeds to swim on her side with great ease, this dream also continuing without awakening. These dreamers were able to execute triumphantly the muscular feats they planned, because they had not really attempted to execute them at all, and, moreover, no sufficient sensory messages reached the brain to give information that the limbs were not actually obeying the orders of the brain. The dreamers were probably in a somewhat deep state of sleep.[80]
The dreams in which we seem to ourselves to be suffering from the difficulty or impossibility of movement thus constitute a special class. Jewell would apply to them the term 'nightmare,' which he regards as 'characterised by inability to move or speak.' When,in dreams, we become conscious of difficult movement, it has frequently, and perhaps usually, happened that the motor channels are not entirely closed, the sensory channels unusually open, and very frequently, though not necessarily, this is associated with the approach of awakening. I dreamed that I was walking with a friend, that we quarrelled, and that thereupon I crossed the road, and walked on ahead of him. These actions seemed entirely effortless. Gradually, however, I became conscious of immense and ineffectual effort in keeping in front, and slowly began to experience, as I awakened, a feeling of lassitude in my actual and motionless limbs. In the process of awakening, I take it, the increased, but still defective, efflux of sensation from the legs, conveying the message of their real position, entered into conflict with the dream imagery, and produced a struggle in consciousness. It is by no means necessary to assume that there was a complete absence of sensory impressions from the legs during the earlier part of the dream; on the contrary, it is probable that the feeling of lassitude was itself the cause of the dream, the idea of walking being a theory to account for the lassitude; this seems more probable than that the actual lassitude was caused by the mental exertion in the dream.
In a dream which a friend tells me he has often had, and always finds painful, he imagines he is climbing a mountain, and at last reaches a point at which, notwithstanding all his efforts, further progress is impossible. It seems probable that this dream is also anexample of the conflict due to the process of awakening. In this case, however, the solution is complicated by the fact that in earlier life the dreamer had really once found himself in the situation he now only experiences in dreams.
It is sometimes possible to prove, through the evidence of a witness, that in our dreams of movements executed with difficulty, we are really sufficiently awake on the motor side to be making actual movements, though these actual movements may only very roughly correspond to the movements we imagine we are trying to make. Very frequently, no doubt, dreams of difficult movement co-exist with, or are caused by, some degree of actual movement. In some such cases, indeed, the slight and imperfect actual movement may, in dream consciousness, be a complete and adequate movement. In these cases the imperfect sensory messages are not, it seems, sufficiently precise to reveal to sleeping consciousness the imperfection of the motor impulses.
Exactly the same thing occurs under the allied conditions of anaesthesia produced by drugs. Thus, on one occasion, when coming to consciousness after the administration of nitrous oxide gas, I had the sensation of crying out aloud, but in reality, as I was informed by a friend at my side, I merely made a slight guttural sound. In the same way we see sleeping dogs making slight movements of all their paws in succession, a faint and abortive movement of running, which in the sleeping dog's consciousness may, doubtless,be accompanied by the notion that he is dashing across a field after a rabbit.
In these dreams of failure of movement, it seems to me, the dream process, as the result of an approximation to the waking state, has become mixed with actual sensori-motor impulses, but the threshold of waking life is still too far off for actual movements to be completely and successfully accomplished, and in the case of the limbs the eye cannot be used to guide movements which the muscular and cutaneous sensations are still too dead to guide. It is important to remember that in waking life, under pathological conditions, we may have a precisely similar state of things. In some states of cerebro-spinal degeneration, resulting in defective sensibility of muscle and nerve, the subject sways unsteadily when he closes his eyes, and when there is loss of sensibility in the arm it is sometimes impossible to hold objects in the hand except with the guiding aid afforded by the eye.[81]
In a dream, dating from fifteen years back, that I now regard as conditioned by the approach of the moment of awakening, I imagined that I was making huge efforts to copy in a copy-book a capital H, engraved in a rather peculiar fashion, but really offering no difficulties to any waking schoolchild. By no meanscould I get the proportions right, if, indeed, I could make any stroke at all, and at the end of my painful and ineffectual efforts I seemed to be trying to write on sand, which was merely displaced by my hand. This final impression seems clearly to be that of a dreamer who is already sufficiently awake to be conscious of the bedclothes yielding to the touch.
The foregoing dream suggests that failure of movement in dreaming may tend to be associated with an accentuation of that shifting of imagery which is one of the most primary elements in dreaming, both failure of movement and accentuation of shifting imagery being, perhaps, alike due to the approach towards the waking state. Thus, if in a dream one is brushing one's coat, one finds, without any overwhelming surprise, that fresh patches of dust appear again and again, even when one's efforts in brushing them away are successful. Even when we feel able to effect movement in our dream, there may still be a failure of that movement to effect its object.
The question of movement in dreams, of the presence or absence of effort and inhibition, is thus seen to be explicable by reference to the depth of sleep and the particular groups of centres involved. In full normal sleep movements are purely ideatory, and no difficulty arises in executing any movement, for the reason that there really is no movement at all, or even any attempt at movement, while, even if slight movement occurs, no message of its actual defectiveness can reach the brain. Movement or attempt at movement, withmore or less inhibition, tends to occur when the motor and sensory centres are in a partially aroused state; it is a phenomenon which belongs to the period immediately before awakening.[82]
It is doubtless mainly due to the diffusion of inhibited nervous impulses through many channels, and the vague and massive character which they hence assume in consciousness, that we must attribute the magnification of dream imagery, and the exaggeration of dream feelings. This is not a constant tendency of our dreams; sometimes, indeed, perhaps in special stages of sleep-consciousness, there is diminution, and people look no larger than dolls, and houses like doll's houses, while, on the emotional side, events which in real life would overwhelm us, may, in dreams, be accepted as matters of course. But the heightening of imagery and ideas and feelings is very common. There is a kind of normal megalomania in our dreams. We have already incidentally encountered many instances of this: a toothappears large enough for a mouse to play in, or like a great jagged rock; the irritation of a mosquito evokes the image of a huge scarlet beetle; in vesical dreams endless streams are seen to flow; a canary's song is heard as Haydn'sCreation, and the howling of the wind becomes a chanted Te Deum.
A French author has written an impressive literary description of his own purely visual dreams, with their magnificent exaggerations and joyous expansiveness, seeking to show that their chief character is their excessiveness; 'the flowers are almost women.'[83]I cannot, however, recognise this as characteristic of normal dreaming. It bears more resemblance to De Quincey's opium dreams, or to the visions which came to Heine as he listened to Berlioz's music. In normal dreaming the imagery may, indeed, be stupendously vast, or fantastically absurd, or poignantly intense. But normal dreams are not built on a consistently colossal scale. The megalomania of dreaming is only accidental and occasional, not systematic.[84]
The heightening of dream experiences may, however, be very complete in, as it were, every direction: thus a botanical friend joined a large party for a pleasant country excursion, in the course of which, while sitting in a waggonette, an acquaintance, a miller, standing in the road, handed up to him a dog-rose. In the course ofa dream of agreeable emotional tone on the night following, this incident was reproduced, but the miller had become an angel, who handed down to him, instead of up from below, a flower which was a moss-rose.
Thus, not only do the actual stimuli taking place during sleep suggest to dream-consciousness imagery of a magnitude out of all proportion to their real intensity, but even the repercussion of the day's incidents in dreams under the influence of a favourable emotional tone may partake of the same heightening influence.
We may say, therefore, that while the excessiveness of dream imagery is mainly due to the conditions of the nervous sensory and motor channels, there is also probably a heightened affectability of the cerebral centres themselves—perhaps due to their state of dissociation or absence of apperception[85]—which leads us in our dreams to react extravagantly to the stimuli that reach the brain. A lady tells me that she often dreams of being very angry at things which, on awaking, she finds are mere trifles that would never make her angry when awake.[86]It is a common experience thatthe things which, in our dreams, impress us as beautiful, eloquent, witty, profound, or amusing, no longer seem so, or only seem so in a much slighter degree, when we are able to recall them awake.
All these various considerations lead us up to a central fact in the psychology of dreaming: the controlling power of emotion on dream ideas. From our present point of view we are now able to say that the chief function of dreams is to supply adequate theories to account for the magnified emotional impulses which are borne in on sleeping consciousness. This is the key to imagination in dreams. From the first we have seen that in dream life the mind is always freely and actively reasoning; we now see what is usually the real motive and aim of that reasoning. Sleeping consciousness is assailed by waves of emotion from various parts of the organism, but is entirely unable to detect their origin, and, therefore, invents an explanation of them. So that in sleep we have to weave theories concerning the unknowable origin of our emotions, just as when we are awake we weave theories concerning the ultimate origin of the totality of our experiences. The fundamental source of our dream life may thus be said to be emotion.[87]
There is certainly no profounder emotional excitement during sleep than that which arises from a disturbed or distended stomach, and is reflected by the pneumogastric to the accelerated heart and the excited respiration.[88]We are thereby thrown into a state of emotional agitation, a state of agony and terror, such as we rarely or never attain during waking life. Sleeping consciousness, blindfolded and blundering, a prey to these massive waves from below, and fumbling about desperately for some explanation, jumps at the idea that only the attempt to escape some terrible danger or the guilty consciousness of some awful crime can account for this immense emotional uproar. Thus thedream is suffused by a conviction which the continued emotion serves to support. We do not—it seems most simple and reasonable to conclude—experience terror because we think we have committed a crime, but we think we have committed a crime because we experience terror. And the fact that in such dreams we are far more concerned with escape from the results of crime than with any agony of remorse is not, as some have thought, due to our innate indifference to crime, but simply to the fact that our emotional state suggests to us active escape from danger rather than the more passive grief of remorse. Thus our dreams bear witness to the fact that our intelligence is often but a tool in the hands of our emotions.[89]
In this tendency, it may be noted, we see the basis of the symbolism which plays so real a part in dreams. Such symbolism rests on the fact that we associate two things—even if the one happens to be physical and the other spiritual—which both happen to imply a similar state of feeling.[90]Symbolism of this kind is, indeed,characteristic of the human mind at all times, in all stages of its development. Thus the physical idea ofheightseems to express also a moral idea, which we feel to be correspondent, while wormwood and gall furnish a taste which enabled men to speak of what seemed to them the correspondingbitternessof death. In dreams this natural tendency of the mind is able to work unchecked and extravagantly. It acts with much facility on any impulse arising from the gastric region, because this region is the seat of various sensations and emotions, both physical and moral, which may thus act symbolically the one for the other.[91]
Even when we realise the process of transformation and irradiation, through which organic sensations can alone reach the brain in sleep, and the inevitable 'errors of judgment' thus produced, it may still seem strange and puzzling to observe how a stimulus which has its origin in the stomach will, by affecting the neighbouring viscera, in its circuitous course along the nerves and through the brain, be transformed, as it may be, into a tragic scene which has never been experienced, nor even deliberately imagined, as for instance—to cite a dreamof my own—in the fiery vision of following a leader, in real life a peaceful and inoffensive man, who, revolver in hand, dashes among foes, shooting and shot at, every moment in danger of life, and always miraculously escaping.
I may illustrate this transformation by the following example: A lady dreamed that her husband called her aside and said, 'Now, do not scream or make a fuss; I am going to tell you something. I have to kill a man. It is necessary, to put him out of his agony.' He then took her into his study, and showed her a young man lying on the floor, with a wound in his breast, and covered with blood. 'But how will you do it?' she asked. 'Never mind,' he replied; 'leave that to me.' He took something up and leaned over the man. She turned aside and heard a horrible gurgling sound. Then all was over. 'Now,' he said, 'we must get rid of the body. I want you to send for So-and-so's cart, and tell him I wish to drive it.' The cart came. 'You must help me to make the body into a parcel,' he said to his wife; 'give me plenty of brown paper.' They made it into a parcel, and with terrible difficulty and effort the wife assisted her husband to get the body downstairs, and lift it into the cart. At every stage, however, she presented to him the difficulties of the situation. But he carelessly answered all objections, said he would take the body up to the moor, among the stones, remove the brown paper, and people would think the murdered man had killed himself. He drove off, and soon returned with the empty cart. 'What's thisblood in my cart?' asked the man to whom it belonged, looking inside. 'Oh, that's only paint,' replied the husband. But the dreamer had all along been full of apprehensions lest the deed should be discovered, and the last thing she could recall, before waking in terror, was looking out of the window at a large crowd which surrounded the house with shouts of 'Murder!' and threats.
This tragedy, with its almost Elizabethan air, was built up out of a few commonplace impressions received during the previous day, none of which impressions contained any suggestion of murder. The tragic element appears to have been altogether due to the psychic influences of indigestion arising from a supper of pheasant.[92]To account for our oppression during sleep, sleeping consciousness assumes moral causes, which alone appear to it of sufficient gravity to be adequate to the immense emotions we are experiencing. Even in our waking and fully conscious states we are inclined to give the preference to moral over physical causes, quite irrespective of the justice of our preferences; in our sleeping states this tendency is exaggerated, and the reign of purely moral causes is not often disturbed by even a suggestion of physical causation.
In an emotional dream of similar visceral origin, I dreamed that I was to die—why or how I could not tellon awakening. With the object of putting an end to my sufferings, I imagined that my wife administered to me some substance mixed in jam. I found the taste peculiar, not bitter, as I recalled on awaking, but warm and spicy, and I asked what she had put in it. She replied that it was strychnine. I remarked that that would be a very painful mode of death, and refused to take any more. I debated with myself whether I had probably taken a poisonous dose, and had not better resort to an antidote; the only antidote that suggested itself to me was opium pills. Meanwhile the horror of impending death grew more and more acute until, at length, I awoke. I thereupon found that I had a headache, a faint taste in my mouth, and some general malaise evidently associated with a slightly disordered stomach. The definite images brought forward in the dream had all been fairly familiar during the previous day, but the idea of impending death which pervaded the whole dream so indefinitely and incoherently, yet so acutely, was entirely a theory to account for the massive and widely irradiated messages of discomfort which reached the sleeping brain.
Many people are unwilling to admit that psychic phenomena so tragical, poignant, or pathetic as these dreams may be, should receive their stimulus from a source which they regard as so humble as the stomach. Thus Frederick Greenwood, whose conception of the function of dreaming was very exalted, only admitted this association with reluctance, and was careful to point out that 'if an unwholesome supper producessuch phenomena, it does so only in the sense that a bird singing in the air produced Shelley's "Ode to a Skylark."'[93]That analogy really underestimates the distance of the physical stimulus of such dreams from its psychic concomitants. When we talk of dreams we must place ourselves at the dreamer's standpoint. The poet was conscious that his inspiration was stimulated by the bird's song, but the dreamer has no consciousness that the tragic experiences he passes through imaginatively are stimulated by the activity of his visceral organs. He is altogether unconscious of visceral disturbance; if he were conscious of any of these physical facts which occupy waking consciousness, he would no longer be a dreamer. He lives in a psychic world which physical facts, from within or from without, can never reach until they have been transformed. His position resembles, therefore, not that of the poet who deliberately seeks to interpret the song of the bird, but rather that of the bird itself, the poet 'hidden in the light of thought,' sublimely unconscious of the mechanism revealed in its own structure.
The explanations devised by sleeping consciousness to account for visceral discomfort of gastric origin are not necessarily tragic. Thus I dreamed, after a somewhat indigestible meal, that I was slowly and painfully eating bread mingled with cinders and mouse's excrement, trying in vain to avoid these impurities, and after the meal was over, finding my mouth full of cinders. On awaking there was no traceable taste or sensationof any kind in the mouth, and the dream was apparently a theory to account for some gastric disturbance. Such a theory seems less far-fetched than that of murder, and probably indicates much less marked and diffused visceral disturbance. Occasionally the explanatory theories of actual sensations accepted by sleeping consciousness are plausible and ingenious, indeed entirely adequate and probable. Thus a lady dreamed that she was drinking glass after glass of champagne, saying to herself the while that she would have to pay for this afterwards. On awaking she found that she was feeling the slight rheumatic pains and discomfort that she was really liable to experience after taking a glass or two of champagne. She had not tasted champagne, or thought of it, for some time previously; the dream champagne was a theory invented to account for the sensations which were actually experienced, though those sensations remained outside dreaming consciousness.
Most of the examples I have presented of the influence of emotion of visceral origin in suggesting dream theories have had the stomach as their source. There can be no doubt that the stomach has enormous influence in this respect; its easily and constantly varying state of repletion, its central position and liability to press on other organs, its important nervous associations, together with the fact that sleep sometimes tends to impede its activity and initiate disturbance, combine to impart to it a manifold and extensive influence over the emotional state in sleep, and atthe same time render the source of that emotional state peculiarly difficult for sleeping consciousness to detect.
It is, however, easy to show that any pronounced or massive feeling continuing or arising during sleep may similarly lead to an emotional state calling for explanation at the hands of sleeping consciousness. Thus, falling asleep with toothache during a singularly close night, I once dreamed that I had committed murder, having apparently killed several persons, and that I was occupied, after arrest, in considering whether my act was likely to be regarded as an unpremeditated act of manslaughter. A headache, again, may be a source of dreams. Thus, falling asleep with headache, I dream that I am waiting for an express train to London; an express comes up to the platform, and I cannot ascertain if it is the train I want. The explanation seems obvious; railway travelling is a cause of headache, and it is therefore put forward in the dream, with accompanying imagery, to account for the sensations experienced. The actual sensation, as is always the case in dreams, that is, the headache, remains subconscious, and, indeed, totally unconscious; the imagery it suggests alone occupies the field of consciousness.[94]An entirely different type of dream may, however,be associated with headache. Thus I once dreamed that I was in a vast gloomy English cathedral, and on the wall I observed a notice to the effect that on such a day evensong would take place without illumination of the cathedral in order to avoid attracting moths. I awoke with slight headache. Here the cool, silent gloom of the cathedral is the symbol of what is desired to soothe the aching head, and the fantastic suggestion read on the notice is merely the theory of dreaming consciousness which knows nothing of the real reason of the wish.
Dreams of murder or impending death or the like tragic situations seem usually to be aroused by visceral stimuli. In some cases, however (as in Maury's famous dream of the guillotine), they are due to an external cutaneous sensation. When the stimulus thus comes from the periphery, the emotional element, even when the dreamed situation is tragic, seems usually (though this is not quite certain) to be less pronounced than when the stimulus is visceral. Thus in a dream of my own, which seemed to be due to a cramped position of the head and neck, I dreamed that I had died (though, somehow, I was not myself, but had become more or less identified with an ugly old woman), and was being autopsied. Then very gradually I became faintly and peacefully conscious of what was going on, though I remained motionless, and all the time believed that I was dead,and that my faint consciousness was merely a part of death. Preparations for the funeral were meanwhile being made, and I was about to be nailed down in my coffin. At this point I became horribly aware that these proceedings would cause suffocation, and, with great effort, I succeeded in moving my arms and speaking incoherently. Thereupon the funeral arrangements were discontinued, and very slowly I seemed to regain speech and the power of movement. But I felt that I must be extremely careful in making any movements, on account of the post-mortem wounds; especially I felt pain in my neck, and realised that it was necessary not to move my head, or the result might be instant death. In such a dream, it may be noted, and in some others I have recorded, we see very instructively the nature of the changes produced in the dream and in the dreamer's attitude by the approach of waking consciousness. The dreamer's relationship to his imagined situation becomes more and more what it would be if the situation occurred in real life, and as soon as there is painful effort and imperfect muscular movement, the coming of waking consciousness is imminent.
The visceral and emotional element in dreaming helps to explain the dreamer's moral attitude and the real significance of those criminal actions in dreams which have often been misinterpreted. Many writers on dreaming have referred, with profound concern, to the facility and prevalence of murder in dreams, sometimes as a proof of the innate wickedness of human nature made manifest in the unconstraint of sleep,sometimes as evidence of an atavistic return to the modes of feeling of our ancestors, the thin veneer of civilisation being removed during sleep. Maudsley and Mme. de Manacéïne, for example, find evidence in such dreams of a return to primitive modes of feeling. Clarke speaks of 'the entire absence of the moral sense' from dreams.[95]Professor Näcke, who has given much attention to the phenomena of dreaming, writes in a private letter: 'What I am amazed at, having perceived it in myself, is the little known fact that a person's character becomesworsein dreaming. Not only the most secret thoughts, wishes, and aspirations become clear, but also qualities which have never been observed before, as, for instance, that one becomes a murderer, an adulterer, etc.' Freud, especially, has elaborated this aspect of dreams as representing the fulfilment of the dreamer's most secret desires.[96]
It may well be that there is an element of truth in the belief that in dreams we are brought back to mental conditions somewhat more closely approaching those of primitive times. It is the manifold variety and complexity of our mental representations which prevent us from responding immediately to impulse under civilised conditions, and when, by dissociation, only a few groups are present to consciousness, the inhibition on violent action tends to be removed. If, therefore, weare more violent, more immoral, more criminal, in our dreams than in waking life, this is by no means necessarily to be regarded as a revelation of our real nature, but is merely an inevitable result of the mental dissociation which prevents many important groups of mental representations from finding their way into consciousness, and at the same time brings all our mental possessions on to the same plane, so that the things we have merely thought or heard of have the same visual reality as our own actual experiences. The sleep of the real criminal, as Sante de Sanctis has shown on the basis of a wide experience, even of criminals guilty of serious acts of violence, tends to be peaceful and dreamless, and such dreams as they have are usually of a simple and innocent sort. If normal people often dream of crime, it is because they are more sensitive and imaginative, and because sleeping consciousness is strained to the utmost to invent a phantasmal tragedy adequate to account for the waves of emotion that beset it.[97]
There is another reason why, in dreams, we may find ourselves engaged in criminal operations. The purely automatic process by which the imagery of dreams is perpetually shifting in pursuit of associations of resemblance or contiguity, leads to confusions which are not rooted in any personal or primitive impulse, as in the example I have previously referred to, of a lady who had carved a duck at dinner, and a few hours later woke upexhausted by the imaginary effort of cutting off her husband's head. Such a dream is merely a mechanical turn of the visionary kaleidoscope, bringing together two unrelated images.
The most potent cause of dream criminality, and especially of murders we have been guilty of before the dream commenced, seems clearly, however, to be that emotional factor of visceral origin which is well illustrated by one or two of the dreams already brought forward.[98]In these cases, again, we are not concerned with any primitive or personal impulse to crime, but we feel ourselves to be so possessed by all the physical symptoms of terror, that the only adequate explanation of our state seems to be the theory that we have committed murder. And if we are more concerned to flee from justice than to experience remorse, that is clearly because the really labouring and agitated heart suggests flight from pursuit far more than any passive emotion.[99]There is, moreover, no more fundamental and primitive emotion than fear.
While these considerations combine to deprive criminal dreams, when they occur, of any great significance as an index of the dreamer's latent morality, I must add that I am by no means prepared to agree thatmoral emotions are so absent from sleep as many writers have stated. There is often a diminished sense of morality, an easier yielding to temptation than would take place in real life, a diminished remorse—these tendencies being mainly due to the conditions of dream-life—but there is frequently a strong sense of morality in dreams, as well as a vivid perception of social proprieties. Those persons who have an unusually strong moral sense, when awake, frequently show, I think, a similar tendency when asleep, but in the dreams of most people moral and decorous considerations seem, as a rule, to make themselves more or less clearly felt, much as in waking life. It may be worth while to bring forward a few dreams which incidentally illustrate the moral attitude of the dreamer.
A lady narrated the following dream immediately on awakening: 'I had murdered a woman from some moral or political motive—I forget what—and had come in great agony to my husband with her shoes and watch-chain. He promised to help me, and while I was wondering what could be done for the benefit of the woman's family, some one came in and announced that a lecture was about to be given on the beauty of nakedness. I then went, with several prim and respectable ladies of my acquaintance [the names were given], into a crowded hall. The lecturer who—so far as appearance is concerned—was a well-known Member of Parliament, then entered and gave a most eloquent address on Whitman, nakedness, ugly figures, etc. He especially emphasised the fact that the reasonpeople are shocked at nakedness is that they usually only see unbeautiful bodies which repel them because they are unlike their ideals. Then he put out his hand, and a naked woman entered the room. Her loveliness was extreme; her form was perfectly rounded, but without suggestion of voluptuousness, though she was not an animated statue, but had all the characters of humanity; she walked with undulating thighs, head slightly drooping, and hair falling down and framing a face that expressed wonderful spiritual beauty and innocence. The lecturer led her round, saying, "This is beauty; now, if you can look at this and be ashamed——" and he waved his arm. She went away, and a beautiful Apollo-like youth, slender but athletic, entered the room, also completely naked. He walked round the room alone, with an air of majestic virility. I applauded, clapping my hands, but a shiver went through the ladies present; their skin became like goose-flesh, and their lips quivered with horror as though they were about to be outraged. The youth went out, and the lecturer continued. At the climax of his oratory, the Apollo-like youth entered, dressed as a common soldier, with no appearance of beauty, and in a rough tone said: "'Ere! I want a shilling for this job." (And I sighed to myself: "It is always so.") No one had a shilling, and the lecturer proceeded to explain to the man that what he had done was for the sake of art and beauty, and for the moral good of the world. "What do I care for that?" he returned, "I want a drink." Then a lady among the audience produced a collar, wrote on ita testimonial expressing the gratitude of those present for the man's services on this occasion, and handed it to me to present to him. "Damn it," he said, "this is only worth twopence halfpenny; I want my shilling!" Then I awoke.' The idea of murder with which this dream began seems to suggest that it may have had its origin in some slight visceral disturbance of which the subject was unconscious, but nothing had occurred to suggest the details of the episode. The interesting feature about it is the presence throughout of moral notions and sentiments substantially true to the dreamer's waking ideas.
In another dream of the same dreamer's the sense of responsibility is clearly present: 'Mrs. F. and Miss R. had called to see me, and I was sitting in my room talking to them, when a knock came at the door, and I found there a poor woman belonging to the neighbourhood, but who also combined in my dream the page-boy at a dear friend's house. From this friend, whom I had not heard from for some time, the woman bore a large letter. She tore it open in my presence, saying, "It says here that the bearer is to open this," and produced from it another letter, a large document of a legal character in my friend's handwriting. When the woman began to open the second letter I remonstrated; I was sure that there was some mistake, that that letter was private, and that no one else ought to see it. The woman, however, firmly insisted that she must carry out her instructions; so we had a long discussion. After a time I called Mrs. F. and appealedto her. She agreed with me that the instructions must only mean that the bearer was to open the outer envelope, not the inner letter. At last I took out five shillings and gave it to the woman, telling her that I would assume all the responsibility for opening the letter myself. With this she went away well satisfied, saying (as she would in real life), "All right, Mrs. ——, you're a lady, and you know. All right, my dear." Then at last I was able to tear open my letter and read these words: "Always use Sunlight Soap." My vexation was extreme.'
On another occasion the same dreamer experienced remorse. She imagined she was in a restaurant, and the girl behind the counter pointed to a barrel of beer—a golden barrel, she said, with a magic key—which could only be opened by the owner. The dreamer declared, however, that she could open it, and, producing a key, proceeded to do so, handing round beer to the bystanders. Then she realised that she had been stealing, and was full of remorse. She asked a friend if she ought to tell the owner, but the friend replied, 'By no means.' This conclusion of the dream seems to indicate that the moral sense, though present in dreams, is apt to be impaired.
In yet another dream this dreamer exhibited a curious combination of moral sensibility and criminal indifference. She imagined that, while walking with a man, a friend, she revealed to him a secret of a woman friend's. Then, realising her betrayal of confidence, she decided that the best thing she could do would be to kill theman. On reflection, however, she thought that it would, after all, be unkind to do so since he was a friend, and so told him that if he ever repeated the secret she would have him torn to pieces. It will be seen that the betrayal of a secret was felt as a far more serious offence than murder. The facility with which, in such dreams as this, the suggestion of murder presents itself, even to dreamers who, when awake, cherish no bloodthirsty or revengeful ideas, is certainly remarkable.
It is often said that in dreams erotic suggestions present themselves with extreme facility, and are eagerly accepted by the dreamer. To some extent there is truth in this statement, but it is by no means always true. This may be illustrated by the following dream, the sources of which could be easily traced; two days before I had seen the gambols of East Enders at Hampstead Heath on a Bank Holiday, and the day before I had visited a picture gallery, the two sets of impressions becoming ingeniously combined, according to the usual rule of dream confusion. I thought that when walking along a country lane a sudden turn brought me to a broader part of the road covered with grass, into the midst of a crowd of women, large and well-proportioned persons, mostly in a state of complete nudity, and engaged in romping together, more especially in tugs-of-war; some of them were on horseback. My appearance slightly disturbed them, I heard one cry out my name, and to some extent they drew back, and partly desisted from their games, but only to a very slight degree, and with no overpowering embarrassment.I was myself rather embarrassed, and, glancing at them again, turned back. Afterwards my walk again brought me in view of them, and it occurred to me that women are somewhat changing their customs, a very wholesome change, it seemed to me. But I remonstrated with one or two of them that they ought to keep in constant movement to avoid catching cold. No erotic suggestions were present, although the dream might be said to lend itself to such suggestions.
The idea of moral retribution and eternal punishment may also be present in dreams. This may be illustrated by the dream of a lady who had an ill and restless girl companion sleeping with her, and was disturbed as well by a yelping and howling terrier outside. She had also lately heard that a friend had brought over a python from Africa. 'I dreamed last night I had a basket of cold squirming snakes beside me; they just touched me all over, but did not hurt; I felt mad with loathing and hate of them, and the beasts would not kill me. That, I thought, was my eternal punishment for my sins.' In her waking moments the dreamer was not apprehensive of eternal punishment, and it may be in such a case that, as Freud suggests, an unfamiliar moral idea emerges in sleep in much the same way as an unfamiliar or 'forgotten' fact may emerge.
On the whole, it may be said that while the moral attitude of the dreaming state is not usually identical with that of the waking state, there still nearly always is a moral attitude. It could not well be otherwise.Our emotional states are intimately bound up with moral relationships; we could not display such highly emotional states as we experience in dreams, with all their tragic accompaniments, in the absence of any sense of morality.
AVIATION IN DREAMS
Dreams of Flying and Falling—Their Peculiar Vividness—Dreams of Flying an Alleged Survival of Primeval Experiences—Best explained as based on Respiratory Sensations combined with Cutaneous Anaesthesia—The Explanation of Dreams of Falling—The Sensation of Levitation sometimes experienced by Ecstatic Saints—Also experienced at the Moment of Death.
Dreams of Flying and Falling—Their Peculiar Vividness—Dreams of Flying an Alleged Survival of Primeval Experiences—Best explained as based on Respiratory Sensations combined with Cutaneous Anaesthesia—The Explanation of Dreams of Falling—The Sensation of Levitation sometimes experienced by Ecstatic Saints—Also experienced at the Moment of Death.
Dreams of flying, with the dreams of falling they are sometimes associated with, may fairly be considered the best known and most frequent type of dream. They were among the earliest dreams to attract attention. Ruths argues that the Greek conception of the flying Hermes, the god who possessed special authority over dreams, was based on such experiences. Lucretius, in his interesting passage on the psychology of dreaming, speaks of falling from heights in dreams;[100]Cicero appears to refer to dreams of flying; St. Jerome mentions that he was subject to them; Synesius remarked that in dreams we fly with wings and view the world from afar; Cervantes accurately described the dream of falling.[101]From the inventors of the legendof Icarus onwards, men have firmly cherished the belief that under some circumstances they could fly, and we may well suppose that that belief partly owes its conviction, and the resolve to make it practical, to the experiences that have been gained in dreams.
No dreams, indeed, are so vivid and so convincing as dreams of flying; none leave behind them so strong a sense of the reality of the experience. Raffaelli, the eminent French painter, who is subject to the dreaming experience of floating in the air, confesses that it is so convincing that he has jumped out of bed on awaking and attempted to repeat it. 'I need not tell you,' he adds, 'that I have never been able to succeed.'[102]Herbert Spencer mentions that in a company of a dozen persons, three testified that in early life they had had such vivid dreams of flying downstairs, and were so strongly impressed by the reality of the experience, that they actually made the attempt, one of them suffering in consequence from an injured ankle.[103]The case is recorded of an old French lady who always maintained that on one occasion she actually had succeeded for a few instants in supporting herself on the air.[104]No one who is familiar with these dreaming experiences will be inclined to laugh at that old lady. It was during one of these dreams of levitation, in which one finds oneself leaping into the air and able to stay there, that it occurred to me that I would write a paperon the subject, for I thought in my dream that this power I found myself possessed of was probably much more widespread than was commonly supposed, and that in any case it ought to be generally known.
People who dabble in the occult have been so impressed by such dreams that they have sometimes believed that these flights represented a real excursion of the 'astral body.' This is the belief of Colonel de Rochas.[105]César de Vesme, the editor of the French edition of theAnnals of Psychical Research, has thought it worth while to investigate the matter; and after summarising the results of aquestionnaireconcerning dreams of flying, he comes to the conclusion that 'the sensation of aerial flight in dreams is simply a hallucinatory phenomenon of an exclusively physiological [he means 'psychological'] kind,' and not evidence of the existence of the 'astral body.'[106]The fact, nevertheless, that so many people are found who believe such dreams to possess some kind of reality, clearly indicates the powerful impression they make.
All my life, it seems to me, certainly from an early age, until recently, I have at intervals had dreams in which I imagined myself rhythmically bounding intothe air, and supported on the air, remaining there for a perceptible interval; at other times I have felt myself gliding downstairs, but not supported by the stairs. In my case the experience is nearly always agreeable, involving a certain sense of power, and it usually evokes no marked surprise, occurring as a familiar and accustomed pleasure. On awaking I do not usually remember these dreams immediately, which seems to indicate that they are not due to causes specially operative at the end of sleep, or liable to bring sleep to a conclusion. But they leave behind them a vague yet profound sense of belief in their reality and reasonableness.
Dream-flight, it is necessary to note, is not usually the sustained flight of a bird or an insect, and the dreamer rarely or never imagines that he is borne high into the air. Hutchinson states that of all those whom he has asked about the matter 'hardly one has ever known himself to make any high flights in his dreams. One almost always flies low, with a skimming manner, slightly, but only slightly, above the heads of pedestrians.'[107]
Beaunis, from his own experience, describes what I should consider a typical kind of dream-flight as a series of light bounds, at one or two yards above the earth, each bound clearing from ten to twenty yards, the dream being accompanied by a delicious sensation of easy movement, as well as a lively satisfaction at being able to solve the problem of aerial locomotion byvirtue of superior organisation alone.[108]Lafcadio Hearn, somewhat similarly, describes, in hisShadowings, a typical and frequent dream of his own as a series of bounds in long parabolic curves, rising to a height of some twenty-five feet, and always accompanied by the sense that a new power had been revealed which for the future would be a permanent possession.
The attempt to explain dreams of flying has led to some bold hypotheses. Freud characteristically affirms that the dream of flying is the bridge to a concealed wish.[109]I have already mentioned the notion that dreams of flight are excursions of the 'astral body.' Professor Stanley Hall, who has himself, from childhood, had dreams of flying, argues, with scarcely less boldness, that we have here 'some faint reminiscent atavistic echo from the primeval sea'; and that such dreams are really survivals—psychic vestigial remains comparable to the rudimentary gill-slits not uncommonly found in man and other mammals—taking us back to the far past when man's ancestors needed no feet to swim or float.[110]Such a theory may accord with the profound conviction of reality that accompanies thesedreams, though that may be more easily accounted for; but it has the very serious weakness that it offers an explanation which will not fit the facts. Our dreams are of flying, not of swimming; but the ancestors of the mammals probably lived in the water, not in the air. In preference to so hazardous a theory, it seems infinitely more reasonable to regard these dreams as an interpretation—a misinterpretation from the standpoint of waking life—of actual internal sensations. If we can find the adequate explanation of a psychic state in conditions actually existing within the organism itself at the time, it is needless to seek an explanation in conditions that ceased to exist untold millenniums ago.
My own explanation was immediately suggested by the following dream. I dreamed that I was watching a girl acrobat, in appropriate costume, who was rhythmically rising to a great height in the air and then falling, without touching the floor, though each time she approached quite close to it. At last she ceased, exhausted and perspiring, and I had to lead her away. Her movements were not controlled by mechanism, and apparently I did not regard mechanism as necessary. It was a vivid dream, and I awoke with a distinct sensation of oppression in the chest. In trying to account for this dream, which was not founded on any memory, it occurred to me that probably I had here the key to a great group of dreams. The rhythmic rising and falling of the acrobat was simply the objectivation of the rhythmic rising and falling of my own respiratorymuscles—in some dreams, perhaps, of the systole and diastole of the heart's muscles—under the influence of some slight and unknown physical oppression, and this oppression was further translated into a condition of perspiring exhaustion in the girl, just as men with heart disease may dream of sweating and panting horses climbing uphill, in accordance with that tendency to magnification which marks dreams generally.[111]We may recall also the curious sensation as of the body being transformed into a vast bellows or steam engine, which is often the last sensation felt before the unconsciousness produced by nitrous oxide gas.[112]When we are lying down there is a real rhythmic rising and falling of the chest and abdomen, centring in the diaphragm, a series of oscillations which at both extremes are only limited by the air. Moreover, in this position we have to recognise that the circulatory,nervous, and other systems of the whole internal organism, are differently balanced from what they are in the upright position, and that a disturbance of internal equilibrium always accompanies falling.
It is also noteworthy (as, indeed, Wundt has briefly remarked) that the modifications produced by sleep in the respiratory process itself tend to facilitate its interpretation as a process of flying. Mosso showed that respiration in sleep is more thoracic than when awake, that it is lengthened, and that the respiratory pause is less marked.[113]That is to say that both the aerial element and the actual rhythmic movement of the ribs become accentuated during sleep.
That the respiratory element is the chief factor in dreams of flying is clearly indicated by the fact that many persons subject to such dreams are conscious on awaking from them of a sense of respiratory or cardiac disturbance. I am acquainted with a psychologist who, though not a frequent dreamer, is subject to dreams of flying, which do not affect him disagreeably, but on awaking from them he always perceives a slight flutter of the heart. Any such sensation is by no means constant with me, but I have occasionally noted it down in exactly the same words after this kind of dream.[114]It is worth while to observe, in this connection, how large a number of people, and especially very youngpeople, associate their dreams of flying with staircases. The most frequent cause of cardiac and respiratory stimulation, especially in children, who constantly run up and down them, is furnished by staircases, and though in health this fact may not be obvious, it is undoubtedly registered unconsciously, and may thus be utilised by dreaming intelligence.
There is, however, another element entering into the problem of nocturnal aviation: the state of the skin sensations. Respiratory activity alone would scarcely suffice to produce the imagery of flight if sensations of tactile pressure remained to suggest contact with the earth. In dreams, however, the sense of movement suggested by respiratory activity is unaccompanied by the tactile pressure produced by boots or the contact of the ground with the soles of the feet. In addition, also, there is probably, as Bergson also has suggested, a numbness due to pressure on the parts supporting the weight of the body. Sleep is not a constant and uniform state of consciousness; a heightened consciousness of respiration may easily co-exist with a diminished consciousness of tactile pressure due to anaesthesia of the skin.[115]In normal sleep it may, indeed, be said that the conditions are probably often favourable to the production of this combination, and any slight thoracic disturbance even in healthy persons,arising from heart or stomach, and acting on the respiration, serves to bring these conditions to sleeping consciousness and to determine the dream of flying.
Dreams of flying are sometimes associated with dreams of falling, the falling sensation occurring either at the beginning or at the end of the dream; such a dream may be said to be of the Icarus type.[116]Jewell considers that the two kinds of dream have the same causation, the difference being merely a difference of apperception. The frequent connection between the two dreams indicates that the causation is allied, but it scarcely seems to be identical. If it were identical, we should scarcely find that while the emotional tone of the dream of flying is usually agreeable, that of the dream of falling is usually disagreeable.[117]