212 JOURNAL OF COMPARATIVE NEUROLOGY. 
side is 119,337. Since, according to my count, the dorsal 
roots (C. V.—Th. I) which help form the brachial plexus, con- 
tain 193,095 fibers, the cutaneous fibers in these roots as 
determined by VoIscHvILLO amount to 61.7%. In consider- 
ing the dorsal roots C. V.—Th. I as the roots giving rise to 
the afferent fibers of the brachial plexus I have made use of P. 
EIsLer’s drawings (Rauber 1893). According to these draw- 
ings the brachial plexus also receives a branch from the roots of 
C. IV and another from the root Th. II (N. intercostobrach- 
jalis). These two sources of gain would make Volscu- 
VILLO’s results too large were it not for the fact that he omitted 
in his estimate the cutaneous fibers given off by root Th. I in 
the N. intercostalis primus, as well as the few cutaneous fibers 
in the rami dorsales of C. V to Th. I. These two factors no 
doubt counterbalance each other to a great extent and thus 
justify us in our calculation 
Again, by adding VolscHviILLo’s averages for the number 
of nerve fibers in the cutaneous nerves derived from the 
lumbosacral plexus of one side, I find them to amount to 154,- 
459 fibers (his own total, by another method which I cannot 
understand, is 82,167). According to my count, the dorsal 
roots (L. II—S. III) which help form this plexus contain 228,- 
117 nerve fibers. In other words, according to VoISCHVILLO’S 
results 67.7% of the nerve fibers in these dorsal roots are 
cutaneous. 
I have omitted the root L. I in this calculation because 
VoISCHVILLO made no estimate of the peripheral nerves de- 
rived from this root. The roots S. IV. S. V, and Coc. I, have 
also been omitted for the same reason. The gain from the root 
of L. I is, no doubt, counterbalanced to some extent by losses 
in branches passing into N. pudendus and N. clunium medius 
which he omitted. 
3. Estimate Based on the Author's Enumeration, Accord- 
ing to the author’s enumeration (INGBERT, 1903) the left dorsal 
roots of the spinal nerves of a large man contain 653,627 
medullated nerve fibers. Since the publication of this report 
the author has made an enumeration of the medullated nerve 
