BRAIN AND NERVOUS SYSTEM. 



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PART VII. 

 BKA1N AND NERVOUS SYSTEM. 



CHAPTER I 



Nervous System. Coverings of Brain. Spinal Cord. Nerves of 

 Sensation and Motion. Distribution. 



747. The nervous system consists of the brain, the spinal 

 cord) and the tierces. The brain is in4he head : its size and 

 shape correspond to the size and shape of the skull. Its ex- 

 ternal surface is not smooth and level, but it is broken into 



FIG. LXII. Brain. External Surface. 



a, Right lobe. b, Left lobe. c, c, Division of the lobes. 



various parts called convolutions, giving <he. organ the appear- 

 ance of a collection of small lobes, with depressions between 

 them, (Fig. LXII.) The substance of the brain is soft and 



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