THE NERVOUS SYSTEM 363 



arrested. They reverberate through the open corridors of the 

 brain. If they are sufficiently noisy to awaken the sleeper, 

 he, detecting them in this path and in that, supposes them to 

 be on the same errands as the impulses which commonly pass 

 thus. If dreams are analysed,, it will be found that, although 

 the combinations of impressions may be uncommon and 

 extremely bizarre, the impressions are selected from the most 

 familiar. The images of which the dream is compounded, 

 which may have lost all normal relations and may have assumed 

 impossible proportions, are those which the mind most fre- 

 quently conjures up. In the large majority of instances some 

 happening of the day preceding can be recognized as the 

 prompting cause. A remembered dream is the photograph 

 taken by consciousness of the sensations which have bom- 

 barded it into activity. Especially if due to impulses originated 

 by visceral discomfort, the dream may have an unpleasant 

 tone. This may take various forms, but the emotion most 

 commonly aroused is fear. The objects visualized may have 

 preposterous dimensions, or they may be not sufficiently dis- 

 tinct for recognition elusive imps ; but most commonly 

 distress is caused by the want of harmony of sensations, due 

 to the absence of kinsesthetic elements. A man is lying on 

 the railway-line ; a train is approaching with increasing speed ; 

 he cannot get up. He is in the pulpit, but cannot speak. 

 Dreams thus confirm the view set forth above as to the cause 

 of volitional action. Ability to perform an act depends upon 

 the flow through the kinaesthetic centres of the brain of im- 

 pulses generated in the muscles by which the act is to be, or 

 is being, performed. Kinsesthetic sensations do not under any 

 circumstances play the same part in mental life as sensations 

 from the skin, the eye, or the ear ; when the body is passive 

 in bed they are not flowing into the cortex. The dream- 

 photograph shows elements demanding movement, but affords 

 no evidence that movement is in progress. 



