5 20 



THE NERVOUS SYSTEM. 



stance, which appears irregularly placed among the fibres, 

 and fills up all the interstices. 



The anatomical distribution of the fibres, both trans- 

 verse and longitudinal, of which the pons is composed, is 

 sufficient evidence of its functions as a conduct or of im- 



Ftff. 138.* 



pressions from one part of the cerebro-spinal axis to 

 another. 



Concerning its functions as a nerve-centre, little or 

 nothing is certainly known. 



Crura Cerelri. The erura cerelri(m, fig. 138), are princi- 



* Fig. 138. Base of the brain (from Quain). |. I, superior longi- 

 tudinal fissure ; 2, 2', 2", anterior cerebral lobe ; 3, fissure of Sylvius, 

 between anterior and 4, 4', 4", middle cerebral lobe ; 5, 5', posterior 

 lobe ; 6, medulla oblongata ; the figure is in the right anterior pyramid ; 



