THE FUNCTIONS OF THE CEREBRAL CORTEX 297 



not, and unconscious cerebration is not consciousness. This is, 

 of course, not incompatible with a dissociation of consciousness 

 into multiple or co-conscious units, as Dr. Morton Prince so 

 forcibly illustrates (The Unconscious, p. 249), though how 

 far in normal men this dissociation may be carried is an open 

 question. 



In my life as viewed by an outside observer there is continu- 

 ity of process, but not necessarily continuity of consciousness. 

 In my own experience consciousness appears to be continuous, of 

 course, because the periods of unconsciousness (as in coma, deep 

 sleep, etc.) do not appear in consciousness; that is, they do not 

 exist for me except as I learn of them by an indirection. In a 

 water mill the function of grinding corn may go on intermittently, 

 though the mechanism is there all the time and the energy is 

 there; but if the water passes from the mill race out over the dam 

 instead of through the water wheel the grinding function ceases. 

 While the mill is at rest changes may be made in the machinery 

 which will modify the character of the grinding when it is re- 

 sumed, but these changes are not grinding. So in the brain the 

 mechanism of consciousness and the structural memory vestiges 

 of past experience may be present continuously; indeed, these 

 vestigeal traces may be linked up in new ways by intercurrent 

 physiological processes. But these things do not constitute con- 

 sciousness. In fact, a large amount of unconscious cerebration 

 may go on, the end result of which alone becomes conscious. 

 The aim of physiological psychology is to clarify not only the 

 mechanism of consciousness, but also all of the antecedent and 

 subsequent physiological processes which are, from the stand- 

 point of an outside observer, demonstrably related to the con- 

 scious processes. It is possible, moreover, to develop a really 

 scientific introspective psychology in which abstraction is made 

 from all of these mechanisms and the individual experiences 

 alone are studied as given in consciousness. This makes up a 

 large part of general psychology. 



Summary. The functions of the cerebral cortex are still 

 largely wrapped in mystery, but the evidence thus far accumu- 

 lated suggests that these functions are, so far as physiologically 

 known, not different in kind from those of the other parts of the 

 brain. It is, however, manifest that these functions are con- 



