ix PSYCHO-PHYSICAL PHENOMENA 453 



conscious workings of the mind the subconscious is active, although 

 every trace of its activity may be instantaneously blotted out 

 from introspection owing, as Myers would say, to the varying 

 permeability of the " psychical diaphragm " which separates the 

 conscious from the unconscious. 



It is further interesting to note that the peripheral sense- 

 organs are pervious to ordinary excitations not only in the waking 

 state but also in sleep ; although we may pay no attention to the 

 impressions they send to the central nervous system if our 

 judgment pronounces them not to be worth attending to. Some 

 people are in the habit of sleeping, and sleeping profoundly, in 

 the midst of noises, as though these were unable to excite the 

 auditory centres during sleep. This, however, is not the case. 

 As James observes, the mother, sleeping amid far stronger noises, 

 awakes the moment the child stirs ; and the same is true of a 

 nurse and patient. This proves that in sleep, independently of 

 consciousness, the auditory centres are not only excited by 

 external sounds, but the mind is also capable of differentiating 

 them and judging of their psychical value. 



Another more commonplace argument put forward by Vaschide 

 to show that unknown to the sleeper the mind is active during 

 sleep is the striking capacity many people possess of knowing 

 the time and measuring its passage in their sleep. They are able 

 to wake up every day at the same moment, and even in some 

 cases at an unusual hour decided on prior to sleeping. This is 

 inexplicable unless we assume an activity of the mind during 

 the entire period in which sensorial consciousness is completely 

 suspended. 



Other arguments to the same effect have been adduced by 

 James from certain curious phenomena observed in hysterical 

 subjects, and proved by Pierre Janet (1889) and Binet (1890) 

 not to be due to deception. 



If we admit the psycho -physical nature of subconscious 

 processes it is evident that they are the continuation of past 

 mental experiences, and are fundamentally derived from the 

 anterior history of the ego. In all probability, as we have said, 

 the conscious psycho-physical processes are not extinguished, but 

 persist even when they become subconscious. Every representa- 

 tion and idea has, as maintained by Gross (1902), a primary 

 function at the moment in which it occupies consciousness, and 

 a secondary function by which it acts in the succeeding moments, 

 and influences the whole of the psychical current, either by 

 facilitating or by obstructing its course. This secondary function 

 comes into play when the consciousness is occupied by other 

 ideas, so that it is either perceived in a vague, confused manner, 

 or not at all. In the first case it enters into the semiconscious, 

 in the second into the subconscious field. 



