THE SPINAL CORD AND CEREBELLUM 121 



muscle of the intestines. It certainly seems as though 

 the fine fibres of the motor or ventral root and those 

 of the sensory or dorsal root were distributed to cells 

 lying very close to one another.* Near to them also 

 is the important group of large cells called Clarke's 

 column, which, although receiving thick fibres from 

 the posterior root, is not on that account necessarily 

 directly connected with muscular sensibility.! 



The thickness of the fibres and the size of the cells Size of 



nerve-cella 



are, as before remarked, factors which cannot be over- and thick- 

 ness of 

 looked. The two usually go together, and betoken fibres as a 



the generation and conveyance of impulses of a certain of func- 

 and, indeed, of a proportionate degree of force. But 

 where are we to look amongst the various forms of 

 nervous action for one which could be said to cor- 

 respond to the^ cells of Clarke's column in this respect? 

 It will be reme'inbered that these cells have been 

 described as large i^nd fusiform, and as being em- 

 bedded in fine fibres. ( This interlacing of fibres, so as 

 to surround a nerve-cell with which they come in 

 contact without being in absolute continuity, is a 

 noteworthy but not exceptional feature of the nervous 

 system. To a greater or less extent it obtains in 

 many regions. When, however, the fibres are espe- 



* Bechterew, loc. ait., p. 44. 



+ Poster, loc. cit., p. 958 : ' It seems natural to infer that the 

 cells forming this vesicular cylinder are connected neither with 

 the ordinary somatic motor fibres governing the skeletal muscles 

 nor with the ordinary afferent sensory somatic fibres coming 

 from the skin and elsewhere, but in some way with some special 

 sets of fibres.' 



