MAURY ON SLEEP AND DREAMS. 391 



We may further presume (and many incidents related 

 confirm this view), that somnambulism chiefly occurs 

 during the time when the cerebral functions are already 

 partially awake another expression of the fact upon 

 which we have so much dwelt, that sleep is a series of 

 states ever fluctuating in kind and degree. We may 

 accredit the statement that the passing dreams of those 

 so affected are rarely remembered ; and yet reconcile 

 this with the view we have just taken of the phenome- 

 non. The startling aspect of somnambulism, and the 

 rarity of its occurrence, have given a mysterious 

 colouring to this condition of sleep, and even made it 

 a theme for dramatic representation, for poetry, and 

 music. Like all other things unfamiliar to us, it is 

 doubtless the subject of much exaggeration in par- 

 ticular instances. But enough remains to render it a 

 striking exponent of these complex relations of the 

 sensorial and other functions, in which so many of the 

 mysteries of life have their source. 



In following the history of sleep and dreams we 

 are perpetually passing from one marvel or mystery to 

 another. It may seem, perhaps, that these terms do not 

 apply to the familiar effect of opiates and other soporifics 

 in producing sleep. But it is this familiarity which con- 

 ceals from us the wonder of the fact, that a mere grain 

 or two swallowed of a particular vegetable extract 

 should have the power for a time of bringing the 

 whole mental arid bodily mechanism under its control ; 

 or that a still more minute quantity of opium or 

 morphia, inserted under the skin, should speedily sub- 

 due the most acute neuralgic pain. A physical cause 



