CH.XVL) THE EVOLUTION OF MIND. 139 



make up by far the largest and most heterogeneous portion 

 01 our psychical life. 



I am inclined to regard these Considerations as very 

 powerful ones, and there are several others which lead to 

 the same conclusion. To present the case properly would 

 require a whole chapter ; but it is not essential for our present 

 purpose that the question should be decided. Whether 

 Mr. Spencer s view of trie respective functions of the cere 

 brum and cerebellum be correct or not, it equally remains 

 true that the class of functions shared by the two are idea- 

 tional functions. They compound in double, triple, quad 

 ruple, or in far higher multiples, the sensory elements already 

 simply compounded by the medulla. And it is in this com 

 pound grouping of impressions, past and present, according 

 to their various degrees of likeness and unlikeness, that 

 thought and emotion, the highest phases of psychical life, 

 consist. 



A moment ago we asked, what is the meaning of the 

 ceaseless interchange of molecular motion which goes on 

 among the innumerable cells of the brain? We now see 

 what is the meaning of it, for there can be but one meaning. 

 The continual redistribution of nervous energy among the 

 cells, is the objective side of the process of which the sub 

 jective side is the recompounding of impressions. If we 

 may for a moment unduly simplify the matter, it may be 

 said that for every renewed grouping of impressions, for 

 every revived association of ideas, there is a nervous dis 

 charge between two or more cells, along formerly-used sets 

 of transit-fibres ; and for every fresh grouping of impressions, 

 for every new connection of ideas, there is a discharge along 

 new transit lines. In reality the matter cannot be so simple 

 nr&amp;gt; this, since, as we shall presently see, the maintenance of 

 consciousness implies a state of tension between many simul 

 taneous discharges. But however great the complexity, the 

 principle remains the same. 



