804 OP THE FUNCTIONS OP THE NERVOUS SYSTEM. 



it has been argued by some, that all our dreams really take place in the moment- 

 ary passage between the states of sleeping and waking; but such an idea is not 

 consistent with the fact already referred to, that the course of a dream may often 

 be traced by observing the successive changes of expression in the countenance 

 of the dreamer. It seems, however, that those dreams are most distinctly 

 remembered in the waking state, which have passed through the mind during 

 the transitional phase just alluded to ; while those which occur in a state more 

 allied to Somnambulism, are more completely isolated from the ordinary con- 

 sciousness. There is a phase of the dreaming state which is worthy of notice, 

 as marking another gradation between this and the vigilant state ; that, namely, 

 in which the dreamer has a consciousness that he is dreaming, being aware of 

 the unreality of the images which present themselves before his mind. He may 

 even make a voluntary and successful effort to prolong them if agreeable, or to 

 dissipate them if unpleasing ; thus evincing the possession of a certain degree 

 of that directing power, the entire want of which is the characteristic of the 

 true state of Dreaming. 



829. Very nearly allied to the states of Somnambulism and Dreaming, are 

 those of Delirium and of Mania, which graduate almost imperceptibly into one 

 another ; being chiefly distinguished by the degree and kind of excitement 

 which they respectively exhibit, and by the nature of the bodily states with 

 which they are connected. The loss of voluntary control over the current of 

 thought is the primary element of both these conditions ; and the gradual weak- 

 ening of this may be frequently traced, when the transition from the normal 

 state is not so rapid as to prevent its various steps from being watched. The 

 artificial delirium produced by intoxicating agents affords peculiar facilities for 

 this kind of observation ; and among these agents, there is none whose operation 

 is so interesting in this respect as the Hachisch. The first effect of a dose of 

 this substance, as described by M. Moreau (Op. cit.), is commonly to produce 

 a moderate exhilaration of the feelings, and an unusual activity of the intellec- 

 tual powers ; but this activity gradually frees itself from the control of the Will. 

 The individual 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 in the least able to 

 trace their origin. These speedily occupy his attention, and present themselves 

 in strange combinations, so as to produce the most fantastic and impossible crea- 

 tions. By a strong effort of volition, however, the original thread of the ideas 

 may be recovered, and the interlopers driven away. These " lucid intervals" 

 successively become of shorter and shorter duration, and can be less frequently 

 procured by a voluntary effort; for the internal tempest becomes more and more 

 violent, the torrent of (apparently) disconnected ideas increases in vehemence, 

 so as completely to arrest the attention, and the mind is at last entirely given 

 up to it, and at the same time withdrawn from the perceptive consciousness of 

 external things, although, as already pointed out ( 828), it is by no means 

 removed from the influence of sensory impressions. The succession of ideas has 

 at first less of incoherence than in ordinary dreaming, the ideal events not 

 departing so widely from possible realities ; and the disorder of the mind is at 

 first manifested in errors of perception, in false convictions, or in the predomi- 

 nance of one or more extravagant notions. These false ideas are generally not 

 altogether of an imaginary character, but are originally called into existence by 

 external impressions, these being erroneously interpreted through the disor- 

 dered action of the perceptive faculty ; thus, for example, among the most com- 

 mon perversions are those relating to time and space, minutes seeming hours, 

 hours being prolonged into years, and all idea of time being at last obliterated, 

 so that past and present are confounded together as in ordinary dreaming : 

 whilst in like manner streets may appear of an interminable length, the people 

 at the other end seeming to be at a vast distance ; the mind having a tendency to 



