THK XKKVni S S1STKM AND ITS < '( >\SKU\ \ Tl< >\ 



is not far from I lie place of entrance of the olfactory fibers 

 into the lower surface of tin- cerebral ina-s (Fig. 2:'>i. 



While these ~e\eral regions of the cerebral cortex have 

 Ix-eii mentioned with especial reference to man, little has 

 lict-n said so far that would not apply as well to the more 

 highly developed animals. It is a question of great 

 moment whether there are to be discovered in the brain 

 clear and well-localized signs of human eminence. As to 

 the answer to this question, there i>. unhappily, a great 

 deal of disagreement. Fifteen or twenty years ago the 

 average writer would have felt warranted in more posi- 

 tive assertions than it is usual to make at the present 

 time. But in spite of conservative tendencies there 

 are some teachings which retain weight for most physiol- 

 ogists. The first and most sweeping of the-e is that the 

 developments in brain organization which correspond with 

 intellectual advance are one sided rather than symmetric. 



Early metaphysicians, like Descartes, were troubled by 

 the dual form of the brain. So long as they emphasized 

 its connection with mind instead of body, such a double 

 character seemed unreasonable. As soon a< men began 

 to view the brain in its relations with the paired muscles 

 and sense organs of the body, its division into right and 

 left halves appeared justified. Hut the desire to find in 

 it some basis for a unity closer than that of two equal 

 and cooperating halves was bound to rise again. Most 

 investigators think that it has been fulfilled in the prob- 

 able fact that one of the hemispheres is dominant and the 

 other subordinate, so far as truly intelligent activities are 

 concerned. 



Most people are ri.iiht handed. This means that the 

 motor area on the left side of the brain has a superior 

 organization, liy this we now understand a superior 

 richness of connections, asocial ion lies \\-jth other regions 

 of the hemisphere. The majority of physiologists will 

 probably o-, , S o far as to say that the machinery of intel- 

 ligence lies more in the left than in the right half of the 

 cerebrum in right-handed individuals. It is supposed that 



