386 



ANATOMY OF THE CENTEAL NERVOUS SYSTEM. 



The eighth cranial nerve consists of two nerves, which have, as is well- 

 known, different functions. It has been proposed, in view of this fact, to 

 separate the two bundles — nervus cochlese and nervus vestibuli — and to 

 consider only the first as the auditory nerve, regarding the other as the 

 tonus nerve. 



The cochlear nerve originates in cells of the spiral ganglion of the 

 cochlea. These cells send out peripherally a delicate branch, which rapidly 



Fig. 245. — The most important features in the region of the origin 

 of the acoustic nerve. 



splits up between the auditory cells (Fig. 16, &), while centrally, analogous to 

 the posterior root from the spinal ganglion-cells to the cord, the auditory 

 nerve-root passes: the nervus cochlea. 



In the section (Fig. 245) one sees how this bundle, earlier known as the 

 "radix posterior," enters with delicate fibers into the above-mentioned 

 nucleus acustici ventralis. It divides into a delicate arborization around the 

 large cells of this nucleus. To a less extent it passes into a relatively small 



