76 



ANATOMICAL AND PHYSIOLOGICAL STUDIES ON 



age. Comparing the values for the height in each turn, we find 

 that from nine days they increase from the basal to the apical 

 turn. This relation can be easily seen in table 47. 



Retzius ( '84) gives in the rabbit and cat the following values 

 (table 48). 



TABLE 47 Condensed 



Ratios of the vertical distance from the membrana basilaris to the surface of the 

 pillar cells according to the turns of the cochlea 



TABLE 48 

 Vertical distance from the membrana basilaris to the summit of the pillar cells 



Table 48 shows that the height of the arch of Corti in the 

 rabbit approximates that in the rat, though there are considerable 

 differences in the earlier stages. In the former the arch of Corti 

 develops after: birth only a little, and is therefore more pre- 

 cocious than in the rat. In the cat the same relation is to be 

 seen, but the absolute values in the latter animal are smaller 

 than in either the rabbit or the rat. 



