GROWTH OF THE INNER EAR OF ALBINO RAT 



103 



there are some fluctuations (table 67, chart 35). In the con- 

 densed table 74 the general relations are shown. The growth 

 of the nuclei of the inner hair cells in diameter is given in table 68. 

 As we see, the diameters increase from birth to nine days, 

 then decrease slowly but steadily. In the three average age 

 groups, however, the values decrease continuously with age. 

 In table 69 are given the values for the volumes of the nuclei 

 of the inner hair cell (chart 34). 



TABLE 74 Condensed 

 Ratios of the volume of the inner hair cells according to the turns of the cochlea 



TABLE 75 Condensed 



Ratios of the diameters of the nuclei of the inner hair cells according to the turns of 



the cochlea 



The ratios of the diameters of the nuclei of the inner hair 

 cells decrease at the earlier ages in each turn from the base to 

 the apex. After nine days they are nearly the same in all the 

 turns (tables 68 and 75), though their absolute values decrease 

 in all the turns after nine days. 



The growth of the outer hair cells. In general, the changes in 

 the volume of the outer hair cells are like those in the inner 

 hair cells. Therefore, the volume increases strikingly up to nine 

 days of age, then gradually to twenty days. The main dif- 



