70 



Journal of Comparative Neurology. 



TABLE II. 



Frog, female, weight 59.5 grams. 



Roots Trunk 



I J I 



= "2 



S 3 B 





138 



199 



8G 



109 



3 ^ 



g a 



513 

 1263 



2838 



2536 



227 

 286 



1 108 

 155 



2789 

 49 



223 



1039 



2743 



2297' 2285 



239 



69 



46 



12 



P V 



7-5 



Explanation of Tables I and II. — These tables contain the records of 

 tlie enumeration of the fibers at different levels of the ventral and dorsal roots 

 and of the nerve trunk of the spinal nerves of the frog. Table I contains counts 

 made upon eight of the spinal nerves of a frog weighing 48.2 grams. Table 

 II, counts of four nerves of a 59.5 gram frog. The figures at the head of the 

 columns indicate the level of the section at which a count was made. For con- 

 venience of reference, each column is designated by a letter. 



The point of principal interest which is claimed for these 

 results lies in the change in the number of fibers to be found 

 in the course of the dorsal and ventral roots and in the course 

 of the trunk between the limits chosen. 



It is first desired to determine whether there is any regu- 

 larity in these variations such as would be exhibited by a per- 

 centage change in the number of fibers for a unit of length. 

 Table I gives the absolute amount of variation in the number 

 of fibers found between the different levels at which the counts 

 were made and thus does not take into account the length of 

 the root nor the distance between the points at which the sec- 

 tions of the trunk were taken. Plate VI will show that these 

 distances through which the changes occur vary greatly for the 



