Volition has no more power over thought when we are awake than sleeping; and, despite all metaphysical and psychological speculations, it cannot be demonstrated that the mind does not retain its full energies during sleep, only they cease to be regulated by judgment, and are not, to use Locke’s words, under the rule and conduct of the understanding; and even on this opinion it has been fairly observed, that much of incongruity which is supposed to prove suspension of reason, and much of the wild discordancy of representation which appears to prevail during our sleep, may arise from the defect of memory when we are awake, that does not retain the impression of images which have passed across the mind in light and rapid succession, and which, therefore, exhibit but a partial and imperfect sketch of the picture that engaged the attention in sleep. The well-known fact that the impressions of our dreams are oftentimes more vivid and correct, when some time has elapsed, than on our awakening, tends to confirm this hypothesis; and these recollections are the more vivid when they bear any analogy to circumstances that come to pass.
Sir Thomas Brown was of opinion that sleep was the waking of the soul; the ligation of sense, but the liberty of reason; and that our waking conceptions do not match the fancies of our sleep. He thus expresses himself in his Religio Medici: “At my nativity my ascendant was the watery sign of Scorpius; I was born in the planetary hour of Saturn, and I think I have a piece of that leaden planet in me. I am no way facetious, nor disposed for the mirth and galliardise of company; yet in one dream I can compose a whole comedy, behold the action, apprehend the jests, and laugh myself awake at the conceits thereof. Were my memory as faithful as my reason is then fruitful, I would never study but in my dreams, and this time also would I choose for my devotions; but our grosser memories have then so little hold of our abstracted understandings, that they forget the story, and can only relate to our awaked souls a confused and broken tale of that that hath passed.”
Dreams have been considered as prescriptive in various diseases. Diodorus Siculus relates that a certain Scythian dreamed that Æsculapius had drawn the humours of his body to one place, or head, to have it lanced. When Galen had an inflammation of the diaphragm, we are told that he was directed in a dream to open a vein between the thumb and the fourth finger—an operation which restored him to health. Marcus Antoninus asserted that he learned in his dreams various remedies for spitting of blood. It is related of Sir Christopher Wren, that, when at Paris, in 1671, being disordered with “a pain in his reins,” he sent for a physician, who prescribed blood-letting, but he deferred submitting to it, and dreamed that very night that he was in a place where palm-trees grew, and that a woman in a romantic habit offered dates to him. The next day he sent for dates, which cured him. Now, although this cure, brought about by a dream, was considered wonderful, its circumstances offer nothing supernatural. It is more than probable that Sir Christopher had frequently read in foreign works on medicine, that dates were recommended as an efficacious remedy in nephritic complaints; and, moreover, had met in his daily perambulations female quacks, who exhibit themselves to this day in the French metropolis, fantastically attired, and vending their far-famed nostrums. That he should have remembered dates, and that the phantasm of the she-mountebank might at the same time have struck his fancy, were two associations by no means improbable.
It is very likely that all the strange stories of prophetic dreams might be traced to a similar connexion of ideas. I have before observed that dreams do not always assume their complexion from recent occurrences, and our bodily sufferings during sleep bring to our recollection every circumstance that regards the malady. A patient who had a bottle of hot water placed at his feet dreamed that he was walking in great agony in the burning lava of Vesuvius. Similar associations exist when awake: the man whose arm has been amputated constantly refers the pain he experiences to the lost hand, or to that part of the limb which received the injury; and the very same nervous illusion prevails during his slumbers. A case is recorded of an officer who had lost his leg, and, when cold, felt comfort and warmth by wrapping the stump of his wooden leg in flannel.
In various diseases the nature and the period of the invasion of dreams afford a valuable ground of observation to the physician both in his diagnosis and prognosis of the case. In incipient hydro-thorax, for instance, dreams occur at the very moment the patient falls asleep, and he fancies himself suffocated by some impending and destructive weight. Diseases of the heart are accompanied by alarming dreams, from which the patient starts up in great terror. In children the perturbation of their sleep frequently indicates the seat of their sufferings; and the valuable researches on the nervous system by Charles Bell have enabled the medical attendant to read in the features of a sleeping infant whether the malady be in the head, the cavity of the chest, or the abdomen.
If proof were wanting that dreams arise from our waking thoughts, it might be found in the circumstance of those sleepers who divulge their secrets, and verify the lines of Shakspeare:
There are a kind of men so loose of soul,
That in their sleep will mutter their affairs.
Reason, therefore, prompts us to reject the idea of dreams being preternatural suggestions. In general, we may consider them as a morbid excitement of the brain, arising either from moral or physical causes, and depending essentially on the condition of our mind and body. Our most lively hopes are ever linked with fears that prey upon us even when most secure; and these apprehensions, recurring in our dreams, prove too often prophetic of the very events we dreaded. The prejudices of early education shed around these forewarnings circumstantial incidents; and fear is the greatest ally of superstition.
If our visions by night are fraught with such singular circumstances, our “day dreams,” or reveries, are frequently attended with strange associations. The impressions received during these ecstatic visions or trances will occasionally act so powerfully upon the mind, that during our waking hours and the usual pursuits of life we cannot divest ourselves of the existence of their reality.
Dr. Arnould has given the following curious account of a case of this kind, as narrated by the individual himself:—“One afternoon in the month of May, feeling himself a little unsettled and not inclined to business, he thought he would take a walk into the city to amuse his mind, and having strolled into St. Paul’s Churchyard, he stopped at the shop window of Carrington and Bowles, and looked at the pictures, among which was one of the cathedral. He had not been long there before a short grave-looking elderly gentleman, dressed in dark brown clothes, came up and began to examine the prints, and occasionally casting a glance at him, very soon entered into conversation with him, and praising the view of St. Paul’s which was exhibited at the window, told him many anecdotes of Sir Christopher Wren the architect, and asked him at the same time if he had ever ascended to the top of the dome. He replied in the negative. The stranger then inquired if he had dined, and proposed that they should go to an eating-house in the neighbourhood, adding that after dinner he would accompany him up St. Paul’s. It was a glorious afternoon for a view, and he was so familiar with the place that he could point out every object worthy of attention. The kindness of the old gentleman’s manner induced him to comply with the invitation, and they went to a tavern in some dark alley, the name of which he did not know. They dined and very soon left the table, and ascended to the ball just below the cross, which they entered alone.