156 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON 



but the differentiation of the papilla, its shifting inward, its 

 change in form and position under the membrana tectoria, appear 

 to be important. 



8. Since the papilla develops from the base toward the apex, it 

 first reaches in the lower turn a high degree of differentiation, 

 and this part first begins to function. Therefore the rat can 

 hear only sounds of high pitch when it first responds. 



9. This result accords with that well-known fact that the 

 papilla in the lower turn responds to sounds of a high pitch, 

 while in the upper turn it responds to sounds of low pitch. 



III. ON THE GROWTH OF THE LARGEST NERVE CELLS 

 IN THE GANGLION VESTIBULARE 



Material and technique 



The material used for the present study was in a great part the 

 same that was employed for the studies reported in chapter 1, 

 with the addition of some new specimens as shown in table 114 

 and table 94. In the slides obtained in the radial vertical section 

 we see the vestibular ganglion cells situated in a single group 

 at the radix of the cochlea (Fig. 3 G. V.). As four ears were used 

 in each age group, four cell groups were examined at each age. 

 Besides these fourteen age groups, six rats used for cross-sections, 

 in chapter 1, were also included. 



The measurements were made in the same way and under 

 the same conditions as those described earlier for the cells of 

 the spiral ganglion. Since the ganglion vestibulare consists of 

 two parts, the ganglion vestibulare superius and inferius, the ten 

 largest cells were taken from each part and the results averaged. 



Observations 



By way of introduction I wish to say a word about equilibration 

 in the young rat. The young just born crawl over on each other 

 and seem to attempt to find the mothers nipples. They turn 

 the head to and fro and roll over on the flanks, belly, or back. 

 While resting they take their normal position or lie on the side. 

 When turned on their backs they endeavor to regain the normal 



