690 



SLEEP. 



ordinary sleep. On the other hand, it may be 

 freely admitted that the apparent duration of 

 our dreams does not afford the least measure 

 of the time they have really occupied; and 

 that it is probable that even when our sleep has 

 seemed most disturbed by them, we have really 

 passed a larger portion of the night in a state 

 of complete unconsciousness than the mere 

 impression left by our dreams would allow us 

 to believe. But it has been questioned by some, 

 on the other hand, whether there is ever 

 such a state as that of complete unconscious- 

 ness. It is affirmed that the mind can never 

 be entirely inactive ; and that every body, in 

 fact, does dream throughout the period of 

 sleep, although the dreams may not be re- 

 membered in the waking state. This state- 

 ment is rather based upon the hypothesis with 

 which it commences, than upon any positive 

 facts ; and as it requires us to give up the 

 simple teachings of ordinary experience, for 

 the reception of a mere metaphysical dogma r 

 the physiologist need not concern himself with 

 the discussion. 



On the whole, it maybe said that dreaming 

 indicates that sleep is imperfect ; and this 

 view harmonises with the fact that between 

 dreaming and the waking state there are 

 various connecting gradations. Thus, reverie 

 or day-dreaming differs from the dreaming of 

 the sleeper, not so much in the condition of 

 the mind and its instrument the cerebrum, as 

 in that of the sensorium, which is not so com- 

 pletely withdrawn in the former case, as it is in 

 the latter, from the consciousness .of external 

 impressions. In sleep, on the other hand, the 

 dreamer may have a consciousness of the un- 

 reality of the images that arise in his mind, and 

 may even make a voluntary and successful 

 effort to prolong them if agreeable, or to dis- 

 sipate them if unpleasing ; thus evincing the 

 presence of that power of control over the 

 current of thought, the want of which is one of 

 the best characteristics of ordinary dreaming, 

 as it is also of insanity, and indicating, there- 

 fore, an unusual approximation to the vigilant 

 condition. 



The action of narcotics on the nervous 

 system presents many curious illustrations of 

 the foregoing statements regarding the nature 

 and phenomena of dreaming. There are some 

 which have the power of inducing every con- 

 dition intermediate between an unusual activity 

 of the thoughts and a state of complete stupor, 

 according to the dose taken. This is the 

 case to ascertain degree with opium; but still 

 more decidedly with the extract of Cannabis 

 Indicn, a preparation of whch, known under 

 the names of Hachisch and Dawamesc, is 

 much used in the East for the production of 

 a species of agreeable intoxication. The first 

 effect of a dose of this substance is usually 

 to produce a moderate exhilaration of the 

 feelings and an unusual activity of the intel- 

 lectual powers ; but this activity gradually 

 frees itself from voluntary control. The in- 

 dividual feels himself incapable of fixing his 

 attention upon any subject ; his thoughts being 



continually drawn off by a succession of ideas 

 which force themselves (as it were) into his 

 mind, without his being able in the least to 

 trace their origin. These speedily occupy his 

 attention, and present themselves in strange 

 combinations, so as to produce the most 

 fantastic and impossible creations. By a strong 

 effort of the will, however, the original thread 

 of the ideas may still be recovered, and the 

 interlopers driven away. These lucid intervals 

 successively become of shorter duration, and 

 can be less frequently procured by a voluntary 

 effort ; for the internal tempest becomes more 

 and more violent, the torrent of disconnected 

 ideas increases in power so as completely to 

 arrest the attention, and the mind is gradually 

 withdrawn altogether from the contemplation 

 of external realities, being engrossed by the 

 consciousness of its own internal workings. 

 There is always preserved, however, a much 

 greater amount of self-consciousness than 

 exists in ordinary dreaming ; the condition 

 rather corresponding with that just referred 

 to, in which the sleeper knoivs that he is 

 dreaming. The succession of ideas has at first 

 less of incoherence than in ordinary dreaming, 

 the ideal events not departing so far from 

 possible realities ; and the disorder of the mind 

 is at first manifested in errors of sense, in 

 false convictions, or in the predominance of 

 one or more extravagant ideas. These ideas 

 and convictions are generally not altogether of 

 an imaginary character, but are called up by 

 external impressions, which are erroneously 

 interpreted by the perceptive faculties. The 

 error of perception is remarkably shown in 

 regard to time and space ; minutes seem 

 hours, hours are prolonged into years, and at 

 last all idea of time seems obliterated, and past 

 and present are confounded together as in 

 ordinary dreaming : and in like manner, streets 

 appear of an interminable length, and the 

 people at the other end seem to be at a 

 vast distance. Still there is a eertain con- 

 sciousness of the deceptive nature of these 

 illusions, which, if the dose be moderate, is 

 never entirely lost. 



The effect of a full dose, however, is at last 

 to produce the complete withdrawal of the 

 mind from any distinct comprehension of ex- 

 ternal things ; the power of the will over the 

 current of thought is in like manner suspended, 

 and the condition of the mind becomes the 

 same in all essential particulars with that 

 of the ordinary dreamer ; differing in this 

 chiefly, that the feelings are more strongly ex- 

 erted, and that they still take their tone 

 almost entirely from external impressions. 

 Thus, says M. Moreau*, " It will be entirely 

 dependent on the circumstances in which we 

 are placed, the objects which strike the eyes, 

 the words which fall on our ears, whether the 

 most lively sentiments of gaiety or of sadness 

 shall be produced, or passions of the most 

 opposite nature shall be excited, sometimes 

 with extraordinary violence ; for irritation 



* Du Hachisch et de 1' Alienation Mentale, Etudes 

 Psychologiques, p. 67. 



