INGBERT, Cutaneous Innervation in Man. 219 
of the dermal surface, the estimates for the cutaneous innerva- 
tion by VOoISCHVILLO will be very nearly the same as that ob- 
tained by myself. 
A study of the following tables makes this apparent : 
Estimate by VOISCHVILLO. 
Area of Dermal Surface 
Dermal area Number of innervated by one cuta- 
Part in sq. mm. Nerve Fibers neous nerve fiber. 
Arm 130,084 119,337 I.1 mm? 
Leg 303,566 154,459 1.9 mm? 
Estimate by Author. 
Area of Dermal Surface 
Dermal area Number of innervated by one cuta- 
Part in sq. mm. Nerve Fibers neous nerve fiber. 
Arm 199,860 152,970 1.30 mm? 
Leg 501,680 204,785 2.45 mm? 
Estimate based on Number of Fibers used by VoiscuviLLo and area 
of dermal surface used by Author. 
Area of Dermal Surface 
Dermal area Number of innervated by one cuta- 
Part in sq. mm. Nerve Fibers neous nerve fiber. 
Arm 199,860 119,337 1.42 mm? 
Leg 501,680 154,459 2.25 mm? 
One factor, however, is not considered in this comparison, 
viz: VOISCHVILLO’s observations being taken at the periphery of 
the body would tend to give him a high number of fibers 
owing to their branching. But as his estimate onthe innervation 
(using the same dermal areas) is very nearly the same as 
that obtained by myself, it is likely that his estimate of the num- 
ber of cutaneous fibers is too low. This agrees with the fact that 
the calculation of the cutaneous nerve fibers in the dorsal roots 
of the spinal nerves based on VoIscHVILLo’s data, gives only 
60 to 67% while that based on my own data gives 79.22%. 
Concerning my own estimate for the innervation of the 
skin, it may be remarked that it is probable that in different 
persons the skin areas differ more than the numbers of nerve 
fibers in the dorsal roots of the spinal nerves, and since I have 
made use of the spinal roots of a large man and the largest 
area of the dermal surface on record, it is probable that if a 
