262 



KENJI NITTONO 



The data in table 20 show that the fibers and axes in the root 

 of the fifth nerve are smaller in diameter than the corresponding 

 fibers in the dorsal root of the seventh cervical spinal nerve. 



Further, the fibers in the ramus ophthalmicus have a less 

 diameter than the largest fibers in the nerve root. If the fibers 

 in the seventh nerve (last column in table 20) are compared with 

 the corresponding root fibers, they are also a trifle smaller, but 

 on the other hand they are much larger in diameter than those 

 of the ramus ophthalmicus. Among these data the fairest com- 

 parison can be made between the fibers from the respective dorsal 

 roots, and this shows the fibers in the dorsal root of the fifth 

 nerve to be much less in diameter than the corresponding fibers 

 for the dorsal root of the seventh cervical nerve, despite the fact 



TABLE 20 

 Diameters of nerve fibers in the fifth cranial and seventh cervical spinal nerves 



that the cells of the gasserian ganglion have the greater diameter 

 and a much higher nucleus-plasma ratio. 



If we turn now to the grow^th changes in the cells forming the 

 two ganglia under discussion, the differences will be most readily 

 brought out by contrasting the amount of growth after puberty. 

 For this we have taken the values at about 80 grams of body 

 weight, using for the gasserian ganglion the data at 85 grams 

 of body weight (table 3) and for the spinal ganglion the data 

 at 81 grams (table 3, loc. cit.). 



Table 21 clearly indicates that between 80 grams of body 

 weight, or just before puberty, and the end of our record there 

 is but very slight growth in the diameter of the cell body or 

 nucleus of the elements in the gasserian ganglion, while the 

 neurons in the seventh cervical ganglion grow very markedl}^ 



