COMMON THINGS MAN. 



its ramifications over the lower arm and hand ; t, those which 

 spread over the trunk ; Jc, /, those which lead to the leg and 

 thigh ; m, n, o, p, their ramifications over the leg and foot. 



The innumerable nervous filaments which are thus spread over 

 the entire system, and which at length become so minute as to be 

 microscopic, are the messengers of thought, carrying the dictates 

 of the will from the brain to all the members, which move in most 



Fig. 1. View of the inferior surface of the human brain, divested of its 

 membranous coatings. 



absolute obedience to the commands thus received. They are also 

 the conductors of sensation from all parts of the system to the 

 1 brain, and are therefore divided into two classes ; the first con- 

 sisting of those which, carrying the dictates of the will to the 

 movable members, are called nerves of motion ; and the second, 

 of those which, conveying sensation from all parts 1 of the body to 

 the brain, are called nerves of sensation. The practical proof 

 that each of these classes of nerves is invested with the special 

 functions here ascribed to them, is found in the fact, that if 

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