The Nervous System 



213 



astride of the back of the cerebro-spinal axis and con- 

 sists of two hemispheres joined by a central mass. On its 

 under surface is a depression which receives the medulla 

 oblongata (Figs. 119 and 121). 



The cerebellum is connected with other parts of the 

 nervous system by strands of white matter on each side, 

 radiating from the 

 center and divided 

 into numerous 

 branches. Around 

 these branches 

 the gray matter 

 is arranged in a 

 beautiful manner, 

 suggesting the 

 leaves of a tree : 

 hence its fanciful 

 name, arbor vitce, 

 or the tree of life. 

 *327. The Func- 

 tions of the Cere- 

 bellum. The 

 functions of the 

 cerebellum are not 



certainly known. FlG - IJ 6- The Upper Surface of the Cerebrum. 

 It aDDCarS tO aid (Showing its division into two hemispheres, and also the 



convolutions.) 



in the control of 



the muscles of the Dody ; that is, it serves to bring the various 

 muscular movements into harmonious action. The mechanism 

 by which it does this has not yet been clearly explained. 

 In an animal from which the cerebellum has been removed 

 the functions of life are not destroyed, but the power of 

 either walking or flying straight is temporarily lost. 



