CHAPTER XIV 

 SUMMARY OF CORTICAL EVOLUTION 



// is an essential prerequisite of consciousness that there 

 should he a period of delay or tension between the receipt of an 

 impression and the determination of the consequent move- 

 ment. — John Fiske 



The function of consciousness is to dislocate in time the 

 reactions from sensations. 



— C. S. MiNOT 



AT the risk of tedious repetition we shall now 

 / % assemble in review the conclusions to which 

 A m. the facts and inferences recounted in the 

 preceding chapters seem to lead. In the interest of 

 simplicity and brevity these conclusions will be enu- 

 merated dogmatically as a series of propositions; but 

 it should be borne in mind that they are not equally 

 validated by unambiguous observation and experi- 

 ment. They represent in part a program for future re- 

 search rather than a digest of equally authenticated 

 facts. 



I. In fishes the beginnings of the cortex are found 

 in correlation centers which do not differ in principle 

 structurally or functionally from other similar cen- 

 ters of the brain stem. The approach toward cortical 

 structure follows change in the nature of the afferent 

 impulses discharged into these centers. Cortical dif- 

 ferentiation tends to be retarded by the dominance 



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