138 



the nuclei in the cells of the lamina pyramidalis being decidedly 

 larger than in those of the spiral ganglion. The ratios of in- 

 crease are, however, similar. 



When we consider the increasing ratios of the diameters of 

 the ganglion cells, we see a close similarity in the maximum values 

 between the cells in the spiral and gasserian ganglion (Nittono, 

 '20). Nevertheless while in the former the ratios from 1 to 20 

 and 1 to 366 days are in the cell bodies 1:1.7 and 1 : 1.6, respec- 

 tively, in the latter the ratios for the corresponding intervals are 

 1: 1.43 and 1: 1.69, respectively (Nittono, '20, p. 235). In the 

 nucleus also similar relations are to be seen in both ganglia. 



As these ratios show, there is in the gasserian ganglion a definite 

 increase in the diameters of cells and nuclei after 20 days of age; 

 the time when the maximum is reached by the cells of the spiral 

 ganglion. Thus the former continue to grow after growth in 

 the latter has ceased. These results suggest that the neurons in 

 the more specialized ganglia, like the spiral ganglion, may mature 

 earlier than do those in the less specialized. 



On the correlation between the growth of the hair cells of the papilla 

 spiralis and of the nerve cells of the ganglion spirale. When we 

 compare the growth changes in the hair cells with those in the 

 ganglion cells, we find that the course of the development is 

 similar. Both classes increase in volume from one to twenty 

 days of age, then tend to diminish slowly the hair cells more 

 slowly than the ganglion cells. In the ratios of increase, however, 

 there are marked differences. Thus in table 67 (bottom of last 

 column) the volume ratios from 1 to 20 and 20 to 546 days are 

 1 : 2.4 and 1 : 0.9, respectively in the hair cells, and in the ganglion 

 cells, table 108, the ratios of the volumes in the fourth column 

 work out for the corresponding ages as 1: 5.1 and 1: 0.8, re- 

 spectively. In the case of the nuclei the growth changes are 

 somewhat different. In the hair cells the nucleus grows in 

 diameter more rapidly, and therefore reaches at nine days its 

 maximum value and then diminishes at succeeding ages. 



I have sought to determine whether there was any correlation 

 in growth between either the entire cylindrical surface or the area 

 of the cross-section of the hair cells, on the one hand and the volume 



