Hardest Y, Spinal Ganglion Cells. 53 



2. In the average there are nearly twice as many nerve 

 fibers in the dorsal root as there are in the ventral root of the 

 Vth, Vlth and IXth nerves. The average is the highest for the 

 Vth and in both the Vth and Vlth is higher than in the IXth 

 nerve. This agrees with the nature of the innervation supplied 

 by the smaller nerves. 



3. As compared with the corresponding trunk, the num- 

 ber of nerve fibers contained in the dorsal branches is reUtively 

 much greater m the Vth and Vlth than in the IXth nerve, 

 while in actual amount, the average number of fibers in the 

 dorsal branches of each of the three nerves is similar. 



4. The distal excess, or the excess in the sum of the fibers 

 of the nerve trunk and dorsal brandies above the sum of the 

 dorsal and ventral roots, occurs to an appreciable extent in every 

 case. While it is less in the nerves of the smaller specimens, 

 its average amount in each of the three nerves of the several 

 specimens is similar. 



5. The percentage of the distal excess ranges higher in 

 the Vth nerve than in the Vlth and it is much higher in both 

 than in the IXth nerve. 



6. There is a general average of three times as many cells 

 in the spinal ganglia as there are fibers in the dorsal roots. And 

 there are more than twice as many ganglion cells as there are 

 fibers in the trunk and dorsal branches less the number of fibers 

 in the ventral root. The average ratios for each of the three 

 nerves are similar, being somewhat higher in the Vth and Vlth 

 than in the IXth nerves. On neither side of the spinal gang- 

 lion do the ratios of cells to fibers show a regular or marked 

 decrease with the increase in body weight. 



7. The distal excess in the three nerves of each specimen 

 increases decidedly and with considerable regularity with 

 the increase in body weight. 'The distal excess increases 

 at a more rapid rate than the fibers in both or in either of the 

 nerve roots, and also at a more rapid rate than the fibers in the 

 trunks and dorsal branches combined or in either separately. 

 With increasing weight, the variations in the ventral roots coin- 



