Donatpson, Law of Innervation. 241 
result of splitting fibers and means—if dichotomous splitting 
be the form assumed—that 343 of the fibers counted at C+S, 
have split later into two divisions each. Just where this split- 
ting occurs, we are obliged to guess. The numerical results 
indicating the number of splitting fibers would be the same, 
whether it occurred in the main stem, C+Si, just where the 
branches to the thigh are given off, or within the branches after 
these had been given off, but before the levels at which they 
were individually sectioned. For the further development of 
our idea of the innervation of the leg, however, these two pos- 
sible arrangements leading to like numerical results, have very 
different values. In the latter instance, where the splitting 
occurs within the branches, the splitting fiber is in no wise rep- 
resented in the main trunk of the nerve below the level of the 
branches, whereas in the former instance, where splitting occurs 
in the main trunk, one division can appear in the branches and 
the other. continue in the trunk, the original fiber being there- 
fore still represented in the trunk, below the point at which it 
has split. 
It was necessary to assume that some of the fibers that 
split did so in the trunk, and thus were represented both in the 
branches and in the trunk below the branches, while others 
split in the branches themselves; both divisions in this case 
having a similar distribution. 
After several tests, it was found that the most accordant 
results were obtained when it was assumed that one-third of the 
splitting fibers split in the branches. Fibers splitting in this 
way form Class a. Since the total number of splitting fibers 
was in this case 343, one-third would be 114.3 fibers. These 
are to be added to the number estimated by me (see Table 
EGVAI 3200 C114. 3-3 333. 3: 
The number of fibers that pass to the shank and foot is 
not affected by this process, since each one of these fibers split- 
ting in the branches is without representation in the trunk 
below the level of the branches. 
By this step 114.3 of the splitting fibers have been with- 
