Reverie, Somnambulism, Hypnotism, /Sleep. 799 



very slightest and almost imperceptible degree, lo lead the way and turn 

 the corners necessary to reach the place. B by yielding to these delicate 

 impulses really follows X instead of leading him as he pretends to do. 

 If X is posted and is on his guard, the element of expectation will be- 

 come deranged and the experiment fail, unless B is a mind reader as 

 well as a muscle reader. 



CHAPTER LXXII1. 



REVERIE, SOMNAMBULISM, HYPNOTISM, SLEEP. 



Attention appears to be the first stage of mental abstraction, of which 

 reverie, absence of mind, somnambulism and hypnotism are further and 

 more intense states. 



The acuteness of sensations depends greatly on the attention they re- 

 ceive. No sensation is produced in sleep by ordinary impressions, and 

 it is the same when the attention is already engaged on something else. 

 On the other hand, impressions which are felt in a slight degree are 

 greatly intensified when the attention is directed to them ; ' < thus, every- 

 one knows how much a slight itching of some part of the surface may 

 be magnified by the direction of the thoughts to it, whilst as soon as 

 they are forced by some stronger impression into another channel, the 

 irritation is no longer felt. " In viewing a landscape we get no idea of 

 details unless the attention is directed successively to each one. If we 

 attempt to sit still by thinking to do so, and directing attention to it, we 

 shall find it difficult, but can easily be perfectly still for a long time 

 when the attention is held by an interesting discourse or spectacle. 



Habit has much to do with the intensity of sensations. The general 

 law is that ' < sensations not attended to are blunted by frequent repeti- 

 tion, "but if attended to their effectiveness is increased by repetition. 

 The direction of the attention is the direction of the blood supply, and 

 when a stimulation comes, it directs the blood to the part of the brain 

 stimulated. If the stimulation is an undesirable one, it is, in part, 

 neutralized or resisted by the stimuli representing this undesirability, so 

 that the attention and blood supply are reduced. Subsequent stimula- 

 tions of the same sort, automatically arouse the antagonistic and neu- 

 tralizing elements which are now in the nature of associated stimuli, and 

 act upon the principle of automatic control set forth in chapter 66. The 

 oftener the process is repeated, the more complete is the neutralization 

 of each other by the antagonist! cal stimuli, and the less sensation and 

 attention they arouse. On the other hand, if the stimulations do not 

 antagonize the organs and conditions already formed, but agree, they 

 will be reinforced by them, and attention intensified by repetition. 



