NERVOUS SYSTEM 



95 



may be related to the somewhat specialized character of the 

 fifth nerve. See table 67. 



Eighth cranial nerve. Droogleever Fortuyn ('14) counted 

 3000 myelinated fibers in the n. cochlearis of the Norway rat. 



For the largest cell bodies and their nuclei in the ganglion 

 spirale, Wada ('23) has made the determinations given in tables 



TABLE 55 



Diameters of the cell bodies and their nuclei in the ganglion spirale (radial-vertical 



section) chart 11 



55 and 56 and chart 1 1 . The values for each group are averages 

 from observations on four cochleae. Table 56 gives the analyt- 

 ical constants based on the measurement of 160 cells in each 

 age group. It may be noted that at nine days — when auditory 

 responses may appear — the cell bodies have only about two 

 thirds of their maximum diameter. This maximum is attained 

 at about the end of suckling (20 days) and after that period 



