THE EVOLUTION OF THE BRAIN 



interfere with the general recognition of the preeminence 

 of the brain as the organ of mind. Why, then, should any 

 difficulty be raised in opposition to the patent fact that the 

 brain itself "in continuance was fashioned," in strict accord- 

 ance with an inherited plan, which is common also to that 

 of our nearest living relations in the animal world? 



I have here called attention to the fact that the rapid 

 development of our knowledge of the human brain and of 

 the effects of injury of disease to different parts of it has 

 made it possible for us to identify the structures whose activi- 

 ties find expression as mind and personality. In the brains 

 of other living creatures corresponding structures can be 

 detected, which conform in every respect except size to those 

 areas which in man we have recognized as the special instru- 

 ments of the mind. The resemblance of the brain of some 

 creatures, like the chimpanzee and gorilla, to the brain of 

 man is much closer than that of either to the brain of any 

 other animal. The only reasonable and satisfying explana- 

 tion of such close resemblances, both in structure and in 

 function, is the inference that (a) these other creatures have 

 the undeveloped germs of a mind similar in kind to man's 

 (one, however, that has definitely lost the power of signifi- 

 cant development or further progress of the kind distinctive 

 of man's immediate ancestors), and (b) that both the brain 

 and the mind of man are the results of a long process of 

 development from ancestors common to those of other living 

 creatures having brains of the same essential type. 



SELECTED REFERENCES 



Smith, G. Elliot. Essays on the Evolution of Man. Oxford Uni- 

 versity Press, 2d ed., 1927. 



Herrick, C. Judson. Introduction to Neurology. W. B. Saunders, 

 Philadelphia and London, 1920. 



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