Donatpson, Law of [nnervation. 251 
at S: This is proof positive of the splitting of the fibers 
within the nerve trunks. Moreover, in our calculations which 
were made to get the estimated number of fibers going to the 
thigh, the average value of the splitting fibers of class ‘‘a”’ 
in these case was 2.9%. For the two shanks of Frog B II it 
was 9.2%, while that demanded for the foot was 9.9%, all 
these percentages being based on the calculated number of 
unbranched fibers to each segment. 
The significance of the foregoing paragraph is the follow- 
ing: When we assume the splitting fibers of this class to this 
amount, the results of the estimation and observation agree 
closely, and that in the shank where good agreement is ob- 
tained, we have assumed 9.2% of these splitting fibers, where- 
as in the foot, at which level our results cannot be tested in 
the same way, but where we should expect a prioria somewhat 
greater number of splitting fibers of this class, we are com- 
pelled to assume only a slightly greater proportion, namely 
9.9 0. 
The claim made, therefore, for the splitting fibers at this 
level of the foot has ample indirect evidence in its favor. 
Just at this point it may be fitting to call attention to the 
fact that the law here enunciated is deduced from the results 
already presented in four different investigations: HarpEsty 
(1899), DonaLpson and SCHOEMAKER (1900), and Dunn (1900 
and 1902), that these were all independent and undertaken 
without any thought of the present problem, and that the data 
taken from them have been here employed without any modifi- 
cation whatsoever. The only special investigation taken up 
after this problem was formulated was the study of the areas of 
skin in the several segments of the leg, and the observation by 
Dr. Dunn on the nerves in Frog C II, with a view to testing 
whether the results on Frog B II might be considered as gen- 
erally applicable. 
This examination of the data from which the deduction 
has been made goes a long way to protect it from the criticism 
of bias, either unconscious or otherwise. 
It has then been possible to show that, allowing fo 
