614 FUNCTIONS OF THE CEREBRO -SPINAL NERVOUS SYSTEM. 



bands which connect the Cerebral mass with the Spinal Cord, but joows through 

 them so as in some degree to isolate the two lateral halves from one another, 

 and to form a complete septum between the anterior and posterior portions 

 of each. These anterior and posterior tracts of the Crura Cerebri are prob- 







FIG. 225. 



Course of the Motor tract, according to Sir C. Bell : A, A, fibres of the Hemisphere, convert-ins to 

 form tlir anterior portion of the ems cerebri ; n, the same tract, where passing the cms cercbri ; c, the 

 ri-.'hl Pyramidal body, a little above the point of decussat ion ; i>, the remaining part of the 1'ons Ya- 

 rolii, :v ])ortiou having been dissected oil' to expose H. 1, olfactory nerve, in outline' ; '1, union of optic 

 nerves; ::.:;, motor ocnli ; 4, 4, pathetieus ; , r >, r>, triijeininiis ; 6, G, its muscular division ; 7, 7, its sensory 

 root ; s, ori;_-iu of sensory root from the posterior part of t lie medulla oblong at a ; !>. ahdncnis oculi ; 10, 

 auditory nerve; ll, facial nerve; r_>, ri^hl li pair; i:i, hypoLjlossal ; 14, spinal nerves; 15, spinal acces- 

 sory of right side, separated from par va^'uiii an<l . 



ably essentially subservient to th^ motor and sensory functions. The gray 

 sulistaiHv of the 1'ons is arranged in a peculiar manner. Its cells are gen- 

 erally round, oval, or fusiform, and of about the yVooth of an inch in diam- 

 eter, and are so connected with nerve-fibres in chains or bundles as to form 



