TRUTH 



ceived from the sense-centres are associated, combined, 

 and united in harmonious thought by them.^ 



The anatomic distinction between the two regions of 

 the cortex which we oppose to each other as the internal 

 sense-centres and the thought or association-centres 

 seems to me of the highest importance. Certain physio- 

 logical considerations had for some time suggested this 

 distinction, but the sound anatomic proof of it has only 

 been furnished during the last ten years. In 1894 

 Flechsig showed that there are four central sense-regions 

 ("internal sense-spheres," or aestheta) in the gray cortex 

 of the brain, and ^.our thought-centres ("association- 

 centres," or phroiieta) between these: the most im- 

 portant of the latter, from the psychological point of 

 view, is the "principal brain," or the "great occipito- 

 temporal association-centre." The anatomic determina- 

 tion of the two "psychic regions" which Flechsig first 

 introduced was afterwards modified by himself and sub- 

 stantially altered by others. The distinguished works of 

 E dinger, Weigert, Hitzig, and others, lead to somewhat 

 discrepant conclusions. But for the general conception 

 of psychic action, and especially of the cognitive func- 

 tions, which interests us at present, it is not necessary 

 to have this delimitation of the regions. The chief point 

 holds, that we can to-day anatomically distinguish be- 

 tween the two most important organs of mental life; 

 that the neurona, which compose both, differ histolog- 

 ically (or in finer structure) and ontogenetically (or 

 in origin) ; and that even chemical differences (or a 

 different relation to certain coloring matters) may be 

 perceived. We may conclude from this that the 

 neurona or psychic cells which compose both organs also 

 differ in their finer structure; there is probably a dif- 



^ Further particulars about the relations of the thought- 

 centres to the sense-centres will be found in the tenth chapter 

 of The Riddle of the Universe. 



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