CH. XLI.] THE CENTRAL NERVOUS SYSTEM 607 



should once more read Chap. XVII. on nerve-centres, in order to 



FIG. 445. View of the cerebro-spinal axis of the nervous system. The right half of the cranium and 

 trunk of the body has been removed by a vertical section ; the membranes of the brain and spinal 

 cord have also been removed, and the roots and first part of the fifth and ninth cranial, and of all 

 the spinal nerves of the right side, have been dissected out and laid separately on the wall of the 

 skull and on the several vertebrae opposite to the place of their natural exit from the cranio-spinal 

 cavity. (After Bourgery.) 



refresh his memory concerning the elementary and fundamental 

 problems in relation to nervous activity in these regions. 



