I 



THE EVOLUTION OF MIND 



the reproduction of impressions received in 

 lower centres, and also involves the coordina- 

 tion of past with present impressions, we may- 

 say that the supreme ganglia are the seats of 

 the higher psychical life, — of memory, reason, 

 emotion, and volition. Dr. Maudsley has thus 

 appropriately termed them the ideational cen- 

 tres. But between the functions of the two, 

 thus closely related, there is nevertheless a dif- 

 ference. Although the precise determination of 

 the way in which ideational functions are shared 

 between the two centres has long remained a 

 puzzling problem, there is good reason for be- 

 lieving that Mr. Spencer has solved the diffi- 

 culty by assigning to the cerebellum the office 

 of doubly compound coordination in space, and 

 to the cerebrum the office of doubly compound 

 coordination in time. The facts of comparative 

 anatomy, and of comparative psychology, so far 

 as known, are in harmony with this opinion. 

 We saw in the chapter on Life and Mind that 

 the extension of the correspondence in time at 

 first goes on parallel with the extension of the 

 correspondence in space — the increased area 

 over which the organism can act being the mea- 

 sure of its increased capacity for adapting its 

 actions to longer and longer sequences in the 

 environment. But we saw also that in the hu- 

 man race the extension of the correspondence 

 in time has gone on far more rapidly than the 



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