If the dreams evoked by sounds within the ear are usually difficult to trace in normal persons under ordinary circumstances, this is not the case with dreams suggested by sounds which strike the ear from without. These constitute one of the most interesting groups of dreams as well as one of the easiest to explain, and they are very frequent.[60] Their mechanism may, indeed, be observed under some circumstances even in the waking state. In some persons, music, a voice, a bird's song, even a word, a comment, arouse phantoms of colour and form, light and shade, coloured clouds, streams, waves, etc. The phenomena are especially rich when produced by an orchestra. Such 'music-phantoms,' as they are termed, are a special and freer development of the narrow and rigid phenomena of 'colour-hearing.' They have been studied by Dr. Ruths.[61] We have to remember that music possesses a fundamental motor basis. As Dauriac remarks, music may be defined as 'movement clothed with sound.'[62] It tends to produce movement, or, failing movement, to produce motor imagery.[63]
Dreams excited by definite external auditory stimuli may be of various character. A not uncommon source—especially for those who live on a wind-swept coast—is the occurrence of storms. A lady dreams, for instance, that her little dog has fallen off a high cliff and that she hears his shrieks; it was an extremely windy night, and her window was open. The dream has some resemblance to one which Burdach recorded that he shared with a companion in an hotel during a storm; they both dreamed they were wandering at night among high precipices.
On one occasion I awoke in the middle of a windy night imagining I had been listening to an opera of Gluck's (which in reality I had never heard), and experiencing all the sense of delicious waves of melody which one actually experiences in listening to such operas as Alceste. A fragment of a melody I had heard in the dream still persisted in my memory on awaking, so that I could mentally repeat it, when it seemed as agreeable as in the dream, though unfamiliar.
The following dream had also a similar origin. I imagined that I was assisting at a spectacle of somewhat dubious erotic character, in company with other persons who, out of modesty, covered their faces with their hands with the decorous gesture which recalled (as dream consciousness evidently realised) that of people during prayer in church. Thereupon a beautiful voice was heard in the background loudly chanting a versicle of the Te Deum. This awoke me, and I seemed to realise when half awake that the voice I had heard in the dream was a real voice. There had, however, been no real voice, only the loud howling of the wind and the beating of the rain on the window panes.
Once, on a very windy night, and when, perhaps, suffering a trifling disturbance of health—for there was slight pleurodynic pain the next morning—I dreamed I was quietly at home with friends, when suddenly the sky became illuminated. We found that this was due to steady and continuous lightning, a state of things which remained throughout the dream, the sky presenting the appearance of a cracked and crushed sheet of melting ice.[64] By and by, fragments of buildings and similar debris were whirled past in the air, and I caught sight of a woman driven above me by her skirts. We now realised the imminent approach of a terrific cyclone which, at any moment, might carry the house and ourselves away. I remembered no more.
Yet another dream may be mentioned as likewise directly due to a violent storm and the rattling of a window near my bed. The latter sound evidently recalled to sleeping consciousness the sound of the rattling window of a railway train, and I dreamed that I was travelling to Berlin with a medical friend. There were the accompaniments, not unfamiliar in dreams, of rushing along interminable platforms, and up and down endless stairs, finding myself in a carriage of the wrong class, with, in consequence, more wandering along corridors, and finally finding that my friend had been left behind. The character of the dream may have been influenced by slight indigestion. In this dream, unlike those already recorded as due to external stimuli, the elements of the dream were not the pure invention of dreaming imagination, but compacted entirely of ideas that had been recently familiar.
The following dream was due to an auditory stimulus of different character. I dreamed that I was listening to a performance of Haydn's Creation, the orchestral part of the performance seeming to consist chiefly of the very realistic representation of the song of birds, though I could not identify the note of any particular bird. Then followed solos by male singers, whom I saw, especially one who attracted my attention by singing at the close in a scarcely audible voice. On awakening, the source of the dream was not immediately obvious, but I soon realised that it was the song of a canary in another room. I had never heard Haydn's Creation, except in fragments, nor thought of it at any recent period; its reputation as regards the realistic representation of natural sounds had evidently caused it to be put forward by sleeping consciousness as a plausible explanation of the sounds heard, and the visual centres had accepted the theory.
However far-fetched and improbable our dreams may seem to the waking mind, they are, from the point of view of the sleeping mind, serious and careful attempts to construct an adequate theory of the phenomena. The imagery is sought from far afield only to fit the facts more accurately. Thus a lady dreamed that her dog was being crushed out flat in a large old-fashioned box-mangle. She awoke to find that water from a burst pipe was falling from the ceiling on to the floor on the landing outside her door, close to where the dog had his bed. She had never seen a mangle of this kind since she was a child, or had any occasion to think of it, but the rhythm and sound of it somewhat resembled that of the falling water.
One more example of an auditory dream may be given. I dreamed that I was back in a schoolroom of my boyhood, with two or three of the present masters. The room had been entirely changed, and it contained much new school apparatus and, notably, on a table, several miniature engines, of different character, actually working. I said to the masters that I wished all these apparatus had been there twenty years ago (a considerable under-estimate of the actual interval since I left that schoolroom), so that I might have enjoyed the benefit of them. 'All life is made up of machinery,' I found myself uttering aloud as I awoke, 'and unless you understand machinery you can't understand life.' It was not till some moments later that I became conscious of a faint whirring sound which puzzled me till I realised that it was the sound of distant machinery entering through the open window. This had, undoubtedly, suggested the engines of the dream, though I had not been conscious in my dream of hearing any sounds, and the small size of the dream engines corresponded to the faintness of the actual sounds.