I:',! ANATOMICAL AND PHYSIOLOGICAL STUDIES ON 



far smaller than on the radial section. This result seems to have 

 some connection with the position of the long axis of the ganglion 

 cells in relation to the axis of the cochlea. 



Comparing the diameters of the cell bodies and their nuclei 

 in nearly corresponding places in the radial and cross-section, 

 the long diameters of the cells are in each age group almost 

 always larger in the radial than on the cross-section. Therefore 

 the cells are somewhat ovoid. The short diameters, however, 

 are at the same age sometimes longer, sometimes shorter on the 

 radial than on the cross-sect'on. This is probably due to the 

 fact that in the upper turns the cells stand with their long diameter 

 more nearly parallel to the axis of the modiolus, and therefore, 

 on passing from the upper to the lower turn, the long axes of 

 the cells become more inclined to the modiolus. 



In order to show that the cell form is ovoid, I reconstructed 

 the cells at 15, 100, and 365 days of age by the usual method, 

 and obtained models which agreed in form with that determined 

 by the microscope. 



It appears, therefore, that while there is some difference in 

 the diameters of these cells according to the plane of the section, 

 neverthless, the change in volume after twenty days is similar 

 in both cases, and so this change does not depend on the plane in 

 which the sections were made. 



On the nucleus-plasma relations of the cells in the ganglion 

 spirale. The computed diameters of the cell bodies and their 

 nuclei, measured on radial sections, are given in table 102 and 

 the nucleus-plasma ratios have been entered in the last column. 

 The ratio is at one day only 1:1.3 and increases rapidly and 

 regularly till twenty days; after that period there are slight fluc- 

 tuations. Generally speaking, the ratios increase with the ad- 

 vancing age of the rat, but after twenty days only very slightly. 

 Thus we see that the nucleus-plasma relation nearly reaches an 

 equilibrium at twenty days, though the cells mature slowly 

 even after that time. 



When we consider this relation according to the turns of the 

 cochlea, we find that this ratio increases in all the turns regularly 

 and definitely till twenty days, after which there are some 



