216 STUDIES IN ELECTRO-PHYSIOLOGY: 



The fifth or trigeminal nerve, it is scarcely necessary to 

 remark, emerges at the side of the pons in two roots, a 

 small motor and a large sensory, and it is only in connection 

 with the sensory nerve that we find the spherical unipolar 

 cells associated. The motor root, as one might expect, is 

 provided with numerous multipolar cells, so that it cannot 

 be said to be entirely distinct from the larger posterior 

 sensory root with which it emerges, inasmuch as any 

 branch of it can be made afferent, although not sensory in 

 the sense of a closed circuit, by the insertion of a bipolar 

 cell between a motor nerve-fibre and a branch. 



Before concluding this study I should like my readers 

 to take careful note that in the course of voluntary motor 

 fibres, before they pass into the anterior root (spinal cord) 

 they always first form connections with the multipolar 

 nerve-cells of the anterior cornu, which, in fact, are intro- 

 duced into the course of the conducting-paths ; but, in 

 their passage through the brain, the paths for direct motor 

 impulses are not interrupted anywhere in their course by 

 ganglion cells, not even in the corpus striatum or pons. 

 They pass in a direct uninterrupted course. 



