THE NERVOUS SYSTEM 29 



ultimately through sensory impulses from the 

 exterior. 



Fragmentary and incomplete as memory is, 

 its performances continually excite our won- 

 der and curiosity, and even from the scien- 

 tific standpoint we are prone to speculate on 

 the methods by which it is brought about. 

 Our common habit of recording and storing 

 as evidence of our experience written or 

 printed signs has given us a figurative concep- 

 tion of the process of memory which is in 

 many respects misleading. We often think of 

 the organ of memory, the cortex, as a place in 

 which is set aside, in some such manner as 

 that just indicated, signs of our experience to 

 be drawn upon as needed. But the cortex is 

 a living portion of our body, and, like other 

 living parts, its life is expressed better in its 

 activity than in its structure, for its structure 

 is forever changing. Memory, therefore, is 

 rather a duplication of a process than the re- 

 appearance of a symbol. It is rather like a 

 current eddy in the flow of our mental life 

 than like a material sign. But it is an eddy 

 which only partially represents the original 

 and carries with it something that separates 

 it from real present experience and marks it 



