Donatpson, Law of Lunervation. 253 
A glance at Table XXV shows (1) that to make the 46% 
of the fibers entering the leg equal the number that will prob- 
ably be observed to the thigh, 5% of itself must be added to it. 
(2) That to make the 25.3% of the fibers entering the leg 
equal the number that will probably be observed to the shank, 
18% of itself must be added to it. 
(3) That to make the 28.7% of the fibers entering the leg 
equal the number that will probably be observed to the foot, 
21.897 of itself must be added to it. 
By the aid of these results, therefore, if one is given the 
number of fibers entering the leg, it is possible to estimate 
with a high degree of accuracy, the number which will be 
found going to any segment. 
(5) The number of medullated fibers distributed as muscular 
and cutaneous nerves to cach segment of the leg. 
The efferent nerve fibers in a given segment are present in 
numbers proportional to the weight of muscle and the afferent 
according to the area of skin. The muscular nerves must 
contain all the efferent or motor medullated fibers, but it would 
certainly be very unexpected to find that the cutaneous nerves 
contained all the afferent fibers. . 
The number of cutaneous and muscular fibers has been 
determined in every instance for both thigh and shank by Dr. 
Dounvy, and with this we can compare the distribution, calculated 
on the assumption that all the afferent fibers have a cutaneous 
distribution. 
In the following table, in each instance, the calculated 
sensory (afferent supply, Cal. S.), is compared with the ob- 
served cutaneous (Obs. Cut.) supply—the calculated number 
always being the /arger. The absolute difference in number of 
fibers is noted and its percentage value given—the number 
forming the observed cutaneous supply, being taken as a stand- 
ard in calculating the percentage. In like manner, the 
observed muscular (Obs. Mus.) supply is compared with the 
calculated motor (Cal. Mot.), the observed muscular supply 
always being the /arger—the absolute difference in number of 
