L16 



ANATOMICAL AM) PHYSIOLOGICAL STUDIES ON 



In the ratios at the bottom of table 89 this is shown very 

 evidently and in each turn this relation is to be seen. 



For the length of the phalangeal process the story is quite 

 different. It increases from birth to twelve days a little; at 

 fifteen days it reaches full size, and then holds its value (table 89). 

 After three days the length is smallest in turn I and largest in 

 turn IV. This relation lasts to old age. 



Comparing the growth of the length of the cell body and 

 phalangeal process, there is a large difference between them. 

 While the length in the phalangeal process is at birth over twice 

 that of the cell body, at 546 days it is only half that of the cell 



TABLE 91 



Total length of Betters' cells — in m {Retzius) 



body. Thus the increase of the total length of Deiters' cells 

 is due chiefly to the increase in the length of the cell body. 



Retzius ('84) gives the length of Deiters' cells in the rabbit 

 and cat as in table 91. 



Table 91 shows that in both the rabbit and the cat the length 

 at all ages is greater, and especially at the earlier stage is twice 

 as great, as in the rat. In the rabbit there is a rapid increase 

 in length between seven and ten days. For the cat the values 

 are smaller, nearer those of the rat, and show less change between 

 birth and thirty days. 



18. Summary and discussion. Using the foregoing data on 

 the form and measurements of the elements of the cochlear 

 dud. I desire here to summarize the results and to discuss the 

 consequent changes in the form of the organ of Corti (table 92). 



