GROWTH OF THE INNER EAR OF ALBINO RAT 



165 



result depends on the fact that the number of the cells here 

 measured is only one-fourth of that measured in the radial 

 section, and hence fewer cells of smaller size were included. 

 At any rate, these ganglion cells in both the radial and cross- 

 sections of the cochlea appear to grow at about the same rate. 

 The statistical constants for these cells and their nuclei are 

 given in tables 121 and 122. 



Discussion 



The nerve cells in the ganglion vestibulare are, as seen from 

 the above description, already well developed at birth both in 

 size and histological structure. After that time they grow con- 



TABLE 120 



Nucleus-plasma ratios of cells of the ganglion vestibulare, in cross-section 



tinuously but slowly so long as followed. The increase from 1 

 to 546 days in the ratios of the diameters is in the cell body 

 1: 1.3, in the nucleus 1: 1.1, and is therefore very small. In the 

 cerebrospinal ganglion cells and in the cells of the cerebral 

 cortex, studied in the albino rat, there is no case which shows such 

 a small rate of increase between birth and maturity. The follow- 

 ing table 123 shows the ratios of increase which have been found. 



It is to be noted that for the cells of the seventh spinal gang- 

 lion and the spinal cord, the ratios were taken from 17 to 360 

 days. If we had the ratios from 1 to 360 days, they would be 

 without question much larger. 



There are a few measurements on the size of the ganglion 

 cells in the vestibular ganglion of various animals in the liter- 



