INGBERT, Cutaneous Innervation in Man. 2h3 
fibers in the ventral roots of the spinal nerves of the same cord. 
This latter enumeration gives 203,700 medullated nerve fibers 
on one, the left, side of the body, or about 407,400 on both 
sides. (The report on this investigation will be published in 
the near future. ) 
As already mentioned, according to SHERRINGTON 
(1894-95) there are two-thirds as many afferent nerve fibers in 
a muscular nerve (a mixed branch to a muscle) as there are 
efferent fibers. We must, therefore, take two-thirds of 203,- 
700 or 135,800 from 653,627 and add them to the efferent 
fibers in order to represent all the muscular nerves. This 
leaves 517,827 nerve fibers to innervate the dermal surface of 
the body; or, in other words, 79.22% of the fibers in the dor- 
sal roots to innervate the dermal surface and 20.78% to supply 
muscles and other deep tissues with afferent nerves. 
4. Comparison and Discussion. For comparison let us 
now repeat these estimates of the number of cutaneous fibers 
the in the dorsal roots: 
I. Estimate Based on STILLING’s Results 60.00% 
2. Estimate Based on VOISCHVILLO’s Results 
a. Brachial plexus 61.70% 
b. Lumbar plexus 67.70% 
3. Estimate Based on Author’s Results 79.22% 
The low figure obtained from STILLING’s data is doubtless 
due to SriLiine’s failure to include the fibers the diameter of 
which is less than 74, as the author has already demonstrated 
(INGBERT, 1903, p. 68), together with the fact that these fibers 
of asmall diameter are more abundant in the dorsal roots, a 
point to be discussed in another paper. We consequently con- 
clude that his figure for the number of fibers in the dorsal roots 
is more below the true one than his figure for those of the ven- 
tral roots. This becomes apparent on a comparison of the 
ratio between the fibers in the two roots. 
Ventral Roots. Dorsal Roots. 
STILLING a 1.66 
INGBERT I 3.20 
The cause of the low figure obtained from VoIscHVILLo’s 
