EVOLUTION OF NERVOUS SYSTEM 81 



THE NERVOUS SYSTEM AND PERSONALITY 



Yet when we examine our systems of organs, we find them 

 quite differently related to our daily activities; the musician 

 trains his ear, the artist his eye, and the athlete his muscles. 

 In this way each one develops a certain individuality or what 

 is commonly spoken of as a personality, to use that term in its 

 more modern connotation. In this sense personality implies 

 an outline of the self, a resume of that body of characteristics 

 that makes up an individual in contradistinction to other indi- 

 viduals. Personality has commonly been regarded as an attri- 

 bute of the body as a whole and yet when it is closely scruti- 

 nized, it is seen to depend chiefly, if not entirely, upon our 

 nervous organization. 



That personality has its seat in the nervous system is in the 

 main a relatively modern view. The ancients for the most 

 part believed that it permeated the whole human frame, and 

 they located what may be called the attributes of personality 

 in the most diverse parts. Thus Aristotle declared the heart 

 to be the sensorium commune of the body and, though he was 

 an unusually acute observer, he was unable to make out any 

 nervous function whatever for the brain. Galen believed the 

 brain to be the seat of the rational soul, but apparently he also 

 accepted the popular belief that the heart was the seat of 

 courage and anger, and the liver that of love. Views of this 

 kind were the prevailing opinions among the ancient writers 

 and show that what we regard nowadays as personality had 

 for them a most broad and general relation to the body as a 

 whole. 



Vesalius, the great anatomist of the sixteenth century, may 

 be regarded as the founder of the modern belief that per- 

 sonality is of strictly nervous origin. In dealing with the 

 nervous system he declares that just as the heart is concerned 

 with the vital spirit, and the liver with the natural spirit, so 



