278 AVERS. 



The Nerve Endings in tJie Ear. 



The fibers of the cochlear nerve, when traced from the 

 twisted cone of medullated fibers in the modiolus outward to the 

 cochlear ganglion, are found to occasionally unite with or give 

 off another fiber, which is not to be regarded as a collateral, 

 since such fiber extends to the hair cells at the periphery in 

 the organ of Corti. In doing so its fibrils do not pass through 

 but around the ganglion cell, through which all the fibrils of the 

 regular nerve fiber must pass. On gaining the ganglion cell 

 the regular nerve fiber issues from the peripheral border of the 

 cell as a single fiber (bipolar cell) or as from two to six distinct 

 nerve fibers (multipolar cell), all of which then take their way 

 towards the organ of Corti, branching as they go. These fibers 

 may leave their radial course at any point and pass at right angle 

 to their former course for greater or less distances (spiral nerve 

 fibers). However, all nerve fibers leaving the cochlear ganglion 

 sooner or later attain the organ of Corti, where they terminate 

 in the bases of the hair cells (first method) or in a sub-acoustic 

 nerve net from which fibers are given off to the hair cells (second 

 method). There is thus formed a compound nerve net disposed 

 in two layers, one above the other, immediately beneath the 

 hair cells, which net serves to connect together hundreds of 

 hair cells in different regions of the epithelial ridge in which 

 the hair cells lie imbedded. Inter-epithelial or free nerve ends 

 may occur, but I have never seen them ; all such cases are 

 apparent, not real, so far as my observations go. The intra- 

 cellular endings are genuine and real, and here, as elsewhere, 

 one positive fact of observation is worth many negative obser- 

 vations. The facts I have stated above are all statements of 

 my positive observations on the basilar membrane, hair cells, 

 hairs, and nerve ends of the human ear. 



UNIVERSITY OF MISSOURI, 



December 10, 1897. 



