ix PSYCHO-PHYSICAL PHENOMENA 477 



to recall it. It has often been noted that it is possible in sleep to 

 recover minute details of distant events, as though impressions 

 once received by the brain were never cancelled. Finally, in 

 dreams we often picture places we have never seen, or events of 

 which we are completely ignorant, or we develop ideas that never 

 occur to us while awake. On the other hand, it is important to 

 note that, according to a census taken by Strieker at the Hospital 

 for the Blind in Vienna, those born blind never dream of seeing, 

 but only of feeling and touching, and that for other blind people 

 the visual images that appear in waking as well as in sleep are 

 infrequent and blurred in proportion to the duration of the blind- 

 ness. 



It is a well-known fact that on waking we forget many of our 

 dreams. The dreams we remember are generally those of the 

 morning at the moment of waking, or when we are dozing off, 

 previous to complete slumber. From this arises the belief that 

 we do not dream for the whole time we are asleep. Goblot states 

 that he is not acquainted with any history of a dream ending 

 otherwise than in waking. A dream is " the commencement of 

 awakening." He affirms that when near waking we are perfectly 

 aware of it, and try to prolong a pleasant and to interrupt an 

 unpleasant dream. In the first instance we try to avoid every 

 possible cause of waking ; in the second we wake purposely by 

 making some movement or opening the eyelids. 



The critical faculty is not altogether suspended in dreams : if 

 the oneiric current assumes too absurd and unreasonable a form, if 

 the hallucinatory images represent strange dangers, we are recalled 

 to a sense of reality and set a limit to our dream ; at other times, 

 on the contrary, we imagine that we are awake while still sleeping. 

 Sleeping and waking are sometimes confounded in consciousness, 

 so that waking up appears to be a displacement of the field of 

 attention. 



It is interesting, again, to note that the oneiric current may 

 sometimes present unconscious intervals, either in automatic 

 dreams or in those suggested by peripheral or internal impressions. 

 Interrupted dreams may be resumed many times and at long 

 intervals. These afford valuable evidence as to the intermittency 

 of consciousness in a long series of co-ordinated oneiric scenes. 



Among the numerous attempts to formulate a theory of 

 dreams, we need only refer to such as to some extent clear up the 

 origin and psychical characters of the oneiric phenomenon. 



Cullen first recognised the strong analogy between the dreams 

 of sleepers and the hallucinations frequently observed in mental 

 diseases and in certain infectious fevers. The different parts of 

 the central nervous system, he says, slumber at different times in 

 various degrees, thus causing a want of harmony in the psychical 

 activity. 



