146 THE SPINAL CORD AND CEREBELLUM 



indeed, if taken alone, should be enough to convince 

 anyone who analyzes the phenomena that the cere- 

 bellum must of necessity contribute a very great 

 amount of force to the muscular system ; otherwise, 

 it may be said, the removal of one-half would not lead 

 to the spasmodic contractions on one side or in one 

 direction which are known to occur, 

 n^iationi"^ The anatomical relations of the cerebellum may 

 the cere- now be briefly considered. It has been described as 



bellum. •' 



a great junction between the cerebral hemispheres 

 on the one hand and the spinal cord and spinal 

 nerves on the other, and it will be seen as we proceed 

 that there are considerable reasons for believing it to 

 be connected with every part of the nervous system, 

 and so with every part of the body. 



The cerebellum is connected with the rest of the 

 nervous system by three pairs of peduncles, the 

 superior, middle, and inferior. The first-mentioned 

 take their origin in the nucleus dentatus, in a small 

 collection of nerve- cells close to it, and in the 

 superficial gray matter. They leave the cerebellum 

 in front and to the median side of the restiform body, 

 and, forming the boundary of the fourth ventricle, 

 pass forward towards the corpora quadrigemina ; con- 

 verging and sinking ventrally beneath these they 

 decussate, and finally end in the red nuclei. Some 

 of the fibres pass by or through these nuclei, and end 

 elsewhere. Each of the superior peduncles, however, 

 through the medium of the red nucleus or in other 

 ways, forms a connection with the cortex of the 



