GASSERIAN GANGLION: ALBINO RAT 253 



THE DIAMETERS OF THE GANGLION CELLS IN RELATION TO THE 

 DIAMETERS OF THE FIBERS 



I wish now to consider the relations between the diameters 

 of the ganghon cells and those of the entire nerve fibers. For 

 this purpose the ganglion cells should be compared with the fibers 

 which belong to the same rat. Such complete data from a single 

 rat were, however, not always available; therefore, I have 

 obtained the approximate corresponding values by the following 

 procedure : 



Smooth graphs for the diameters of the cells and of the fibers 

 were drawn on the brain weights corresponding to the observed 

 body weights (Donaldson, '15), and from the graphs thus drawn 

 the missing values for the diameters of the cells or of the fibers, 

 respectively, were read. The data so obtained were then tabu- 

 lated in detail. 



In order to see more clearly the relation between the ganglion 

 cells and the nerve fibers, table 15 was prepared from these de- 

 tailed data. In table 15 the entire data were arranged in nine 

 groups, which enable one to compare the average diameters of 

 the largest nerve cells in the gasserian ganghon with the corre- 

 sponding average diameters of the largest myelinated fibers, or 

 their axis cylinders, arising from them, taken from the first, 

 second, and third branches and from the fifth nerve root. 



Looking at the series of ratios at the bottom of table 15 show- 

 ing the increase in the diameters of the cells as compared with 

 those of the fibers, it appears that while the cells increase 1.39 

 times, the four sets of fibers have increased between 2.78 and 

 2.05 times, while the increase in the axis cylinders is greater in 

 general than that for the entire fibers, ranging from 3 to 2.41 

 times. 



To illustrate the changes in the ratios from the first to the 

 last group in table 15 we have made table 16, giving for each 

 branch and for the fifth nerve root the ratios obtained by dividing 

 the diameters of the cells by the diameters of the respective 

 nerve fibers. This table shows that the ratios decrease in general 

 frorii the first to the last groups, and this result is merely a con- 

 sequence of the fact that the fibers are growing in diameter more 



