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fore, are no longer present. In the second place, the anatomical conditions are different during dreaming from what they are during perfect sleep. These are proved by the two facts, taken in conjunction, that "dreams usually occur between sleeping and waking," and that between the state of the circulation which characterises perfect activity and that which characterises perfect repose there are intermediate conditions of the various faculties. Again, in some parts of the brain the circulation of function may prevail, while in other parts the circulation is of that kind which is most favourable to nutrition. Thirdly, we may conclude that an essential psychological difference must exist between the sleep of utter unconsciousness and the partial sleep disturbed by dreams, because the more continuous and uninterrupted is our dreaming the less refreshing is our sleep; in other words, the less complete and perfect has been the repose of the brain, the less capable is it of vigorously reassuming the exercise of its various functions. This local or general activity of the cerebral circulation, greater than that which is associated with entire suspension of function, characterises that peculiar condition of the brain's functional activity which we call dreaming. And since dreaming indicates a certain amount of cerebral activity, no sleep can be perfect in which dreaming occurs.'-The Physiology of Sleep. Guy's Hospital Reports. Third Series, vol. vi., 1860.


SIR BENJAMIN C. BRODIE, BART., D.C.L., ETC. 'During what may be called sound sleep, those impressions on the external senses of which we take cognizance while we are awake are altogether unnoticed. But it is not so with regard to the changes which are taking place in the brain itself; and that which constitutes the imagination during the day is the foundation of our dreams at night. There is, however, a great difference in the two cases.

The imagination, while we

are awake, is regulated by the will. We can arrest visions as they pass before us, compare them with each other, and dismiss them as we please. But it is not so with our dreams at night. Here the visions which arise, uninfluenced by the will, succeed each other according to no rule with which we are acquainted, forming strange combinations, often wholly unlike anything that really occurs, and not less differing from reality in the rapidity with which they come and depart. You are called in the morning, and fall asleep again. Perhaps you have slept only one or two minutes; but you have had a long dream. The late Lord Holland was accustomed to relate the following anecdote of what had happened to himself. On one occasion, when he was much fatigued, while listening to a friend who was reading aloud, he fell asleep, and had a dream,



the particulars of which it would have occupied him a quarter of an hour or longer in writing. After he awoke, he found that he remembered the beginning of one sentence, while he actually heard the latter part of the sentence immediately following it, so that probably the whole time during which he had slept did not occupy more than a few seconds. Mr. Babbage had a similar opportunity of measuring the real duration of a dream. While travelling with a friend in Italy, being much wearied, he fell asleep, and dreamed a succession of events as having occurred in England. When he awoke, he heard the concluding words of his friend's answer to a question which he had just put to him. I mention these things, however; only in the way of illustration, and not as being of any very unusual Occurrence. Similar instances are referred to by Lord Brougham in his "Discourse on Natural Theology," and may, if we look for them, be found within the range of our individual experience. If we were to pursue this subject, it would lead us to some curious speculation as to our estimate of time, and the difference between the real and the apparent duration of life. The measure of time which we make by our own feelings is a very different matter from that which uncivilised man makes by the moon and stars, and which we now make by clocks and almanacks. The apparent duration of life is longer or shorter in proportion as a greater or




smaller number of different states of mind follow each other in succession. To a child, whose imagination is constantly excited by new objects, and whose temper passes more easily from one passion to another, a year is a much longer time than to the grown-up man. As we advance in age, so do the years pass more rapidly. We may suppose the life of a butterfly, which exists only for a single season, to be apparently longer than that of the slowly-moving tortoise, whose existence is prolonged for one or two centuries; and that there is a similar difference, though in a less degree, between the life of the enterprising man, whose progress is crowded with events, and with alternate hopes and fears, and that of another who, with more limited desires, keeps "the even tenor of his way."

'During sleep ordinary impressions pass unnoticed. But impressions of a stronger kind rouse the attention, and in so doing put an end to sleep; while those of an intermediate kind affect us in another way, by giving a peculiar character to our dreams. A remark was made in one of our former conversations, referring to acid in the stomach, and some other cases, as illustrating the subject. It occurs to me to add another example to those which have been adduced. It lately happened to myself to dream that some one had given me a shellfish in a shell something like a muscle; that I ate it; and that, after it had been swallowed, I felt it to be



very acid, and that it produced a pain in my throat. When I awoke, I found that I laboured under a sore throat, which must have suggested the dream. It is a curious fact that we may have a long dream in the act of awaking from our sleep. A military officer informed me that, while serving in the Peninsular war, he had frequently been roused from his sleep by the firing of a cannon near his tent; and that he had a dream, including a series of events which might be distinctly traced to the impression made on his senses by the explosion. Facts of this kind have inclined Lord Brougham to the opinion that we never dream except while in a state of transition from being asleep to being awake. But I own that this seems to me to be a mistake. First, there is no sufficient proof of its being so; and secondly, we have a proof to the contrary in the fact that nothing is more common than for persons to moan, and even talk, in their sleep, without awaking from it. Even in the case of a dog, who is sleeping on the rug before the fire, if you watch him, you can scarcely doubt that he is sometimes dreaming, though he still remains asleep. I should myself be more inclined to doubt whether we ever sleep without some degree of dreaming. At any rate not to dream seems to be, not the rule, but the exception to the rule; for it rarely happens that we awake from sleep without being sensible of some time having elapsed since we fell asleep; which

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