168 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON 



at 546 days is relatively slight as compared with what takes 

 place in the cells of the ganglion spirale. It appears, therefore, 

 that the cells in the vestibular ganglion are at birth in a more 

 mature condition. 



As to the correlation between the development of the ganglion 

 cells and the equilibrium function, we have noted that the albino 

 rats, even just after birth, show some sense of equilibrium, 

 though the movements are lacking in coordination. With ad- 

 vancing age the balance of the body is held much better and all 

 the movements gradually become coordinated. The histological 

 structure and the size of the cells at birth suggest that they are 

 functional at that time, and the later increase in the volume 

 and maturity of the cells is accompanied by a corresponding 



increase in the functional development. When the tactile sense 

 is well developed and the eyes open equilibrium is almost perfected. 

 It is a well-known fact that these two senses have very in- 

 timate relations to the maintenance of equilibrium. In this case, 

 as we might expect, the early development of a function is 

 accompanied bj r an early maturing of the neural mechanism 

 on which it depends. 



Conclusions (for the ganglion vestibulare) 



1. The measurements were taken on the largest nerve cells 

 of the ganglion vestibulare in the radial section of the cochlea, 

 and the developmental changes during portnatal growth studied 

 in fourteen age groups, comprising four ears in each group. 

 Further, in six age groups the cell size was determined in cross- 

 sections. The results have been given n tables 115 and 118 

 and charts 43 and 44. 



