328 BRAINS OF RATS AND MEN 



be projected into the future, thus permitting predic- 

 tion of future events, adjustment of present behavior 

 with reference to future contingencies, and the fabri- 

 cation of conscious purposes. 



Hunter (1924) has analyzed the mechanism of the 

 symbolic process, and his analysis in objective terms 

 is all to the good. To be sure, his neurologic schema 

 is purely hypothetical, but it is as good as any other 

 hypothesis and it is helpful in impressing upon us the 

 very elusive fact that every mental act is the function 

 of some special anatomical configuration of parts.^ 



In the neurologic diagram presented by Hunter, a 

 considerable part of the schema is necessarily hypo- 

 thetical because we do not know all of the connections 

 of the parts which are activated when we say the 

 word "box*' upon seeing this object. But a similar 

 schema designed to illustrate the connections of parts 

 activated when my biceps muscle contracts reflexly in 

 response to a pin prick would likewise have to be filled 

 in by wide stretches of hypothetical construction. We 

 do not know exactly how a sense organ is excited, 

 how a nerve fiber conducts, how a muscle contracts, 

 how a gland secretes, or how the brain thinks, though 

 we have satisfactory evidence that all of these organs 

 do perform the functions mentioned. No biologist 

 with all of the evidence before him can fail to make 

 this deduction. Why some other people accept the 



' For other schemata of these cortical processes, see Bianchi (1922, 

 pp. 245-251) and Cole (1925). 



