MANNER OF AWAKENING. 553 



the heart and the lungs act more slowly but more powerfully ; a gentle 

 delirium, which exists while the centres of the special senses are coming 

 into repose, introduces us to profound and unconscious sleep. 



This condition of profound sleep, though it may be quickly, is yet 

 gradually reached by passing through certain well-marked p rog ress of 

 stages. Once gained, we sleep with heaviness in the early night-sleep. 

 part of the night, and more and more lightly as morning approaches. 

 It would, however, be erroneous to suppose that this falling into insensi- 

 bility and awakening are perfectly continuous events ; there are, undoubt- 

 edly, subordinate periods of more and less complete repose, but under 

 no circumstances are we ever aware that we are asleep. 



At any time of the night sleep may be abruptly broken, the mind re- 

 suming its power after passing through a momentary interval Manner of 

 of confusion. Toward the close of the customary time, the awakening, 

 senses resume their power in an order inverse to that in which they lost 

 it the touch, the hearing, the smell, the sight. For a short period after 

 awakening, the organs seem to be in a state of unusual acuteness, more 

 particularly that of sight an effect arising from the obliteration of the 

 vestiges of old impressions. From profound sleep we pass to the wak- 

 ing state through an intermediate condition of slumber. In the former, 

 the movements which we may execute, under the influence of external 

 impressions, are wholly of an automatic kind, such as turning in bed in 

 various positions. The -length of time spent in sleep and slumber re- 

 spectively is by no means constant, many causes increasing the one at 

 the expense of the other. On awakening, we are apt to indulge in cer- 

 tain muscular movements we rub our eyes, stretch, and yawn. If we 

 are suddenly aroused, our motions are feeble and uncertain on attempt- 

 ing to walk at once ; but if we spontaneously awake at an unusual period, 

 and more particularly if it be toward the morning, we commonly remark 

 a clearness of intellect or mental power. Many of our most judicious 

 and correct conclusions occur to us under these circumstances. 



Though it is said that the sleep of man lasts about eight hours, there 

 are many variations. Authentic cases are on record in which M aximuin and 

 individuals have, for a considerable time and apparently with- minimum 

 out injury, slept only for one hour, and others in which that engt 

 state has been prolonged for an entire week. Man shows much greater 

 differences than other animals ; birds, for instance, sleep lightly, and cold- 

 blooded animals generally profoundly. Since the object of sleep is to 

 afford an opportunity for repairing the waste of the system, the length 

 of the needful time depends on conditions that are themselves variable : 

 the extent of the antecedent waste, and the rapidity of the repair. In 

 winter we sleep longer and usually deeper than in summer, for the hour- 

 ly waste in winter is greater. Habit, however, controls us very much. 



