36 Journal of Comparative Neurology and Psychology. 



1. When the different nerves of each specimen are consid- 

 ered indidually, the number of fibers in the nerve trunk (col. A) 

 and those in the dorsal branches (col. B) do not show a regular 

 increase with the increase in body weight. The same is true 

 for the sums of these fibers in the three nerves of each speci- 

 men (col's. C and L). However, though the increase is not a 

 regular one, the larger specimens have appreciably more fibers 

 than the smaller ones. The same statements apply to the num- 

 bers of fibers in the dorsal and ventral roots (col's. D and E). 



2. It is evident here (col's. C and D), and especially so 

 when computed (see Table IV), that in the dorsal and ventral 

 roots the increase of fibers with the increase in weight is not so 

 great as in the trunks and dorsal branches. In other words, 

 the fibers on the side of the distal excess increase more rapid- 

 ly than on the central side of the spinal ganglion. 



3. While the amount of the distal excess in each nerve 

 (col. F) varies so greatly that its increase with the body weight 

 is not very evident, yet when the sums of the distal excesses 

 in each set of nerves are considered (col. G) there is manifest 

 a decided and nmch more regular increase. 



4. The most marked increase in the sums of the distal ex- 

 cess appears in this series between the weights of 25 and 61 

 grams. Between 25 and 33 grams the increase amounts to 27% 

 and in passing from 33 to 47 grams the increase amounts to 

 23%, while the average increase from from one specimen to the 



Table III. Giving number relations involving the distal excess. The 

 ▼arious columns are either rearranged or derived from the columns of Tables I 

 and II. The sums in columns C, D and G result from adding in adjacent col- 

 umns the numbers found respectively in the three nerves of each specimen. The 

 percentages in col. J result from dividing the sums in col. G by the respective 

 sums in col. D of Table II ; the percentages in col. K from dividing col. G by 

 the respective sums of ventral root fibers in col. C of Table IV. The sums in 

 column P are obtained by substracting col. D of Table II from col. C of that table 

 and the ratios in the last column result from dividing the numbers in col. P of 

 this table by the sums in col. G. As indicated in the headings, all the other col- 

 umns set in heavier type are derived from columns accompanying them in this 

 table. The percentages are reduced to one decimal figure and the ratios are 

 given in round numbers. 



