ii6 THE SPINAL CORD AND CEREBELLUM 



these two tracts, it is difficult to see why the degenera- 

 tion should be on both sides of the cord when it 

 is started in the cerebrum instead of the cerebellum, 

 although the absence of degeneration in the fibres of 

 the idiolateral group on the opposite side to the 

 lesion in the hemisphere remarked by Bechterew 

 would agree with the facts as related by Poster. 

 Whatever may be the explanation of these apparently 

 contradictory facts, it is noteworthy that severance of 

 the inferior peduncle or removal of one-half of the 

 cerebellum causes degeneration on the same side in 

 the pyramidal tract and anterior roots of the spinal 

 nerves ; for this certainly seems to suggest that the 

 cerebellar system may be concerned, to some extent, 

 in keeping up the nutrition of the larger or cerebral 

 system, and it will be seen later on that this fact 

 does not stand alone. 



As to the functions of the fundamental groups of 

 fibres, the anterior and the lateral, very little can be 

 definitely asserted. Some of the fibres of the anterior 

 portion have been traced to the posterior horn and 

 Clarke's column of the opposite side, some to the 

 anterior, and some to the lateral horn of the gray 

 matter. The fibres of both portions are for the most 

 part short, and run up and down the cord in branches 

 or arborescences round motor or other cells.* The 



* Bechterew, loc. cit., p. 81. Page 78 : ' Weiterhia ist in den 

 Vorderstrang Grundbiindeln ein Fasersystem enthalten, welches 

 unter Kreuzung seiner Elemente durch die vordero Kommissur 

 hindurchgeht und in Nervenzellen des Hinterhornes vind ins- 

 besondere der KJarkeschen Saulen wurzelt.' 



