IncBERT, Dorsal Roots of Spinal Nerves. 67 
times. Ido not believe, however, that the error from sources 
(a) and (b) exceed 2% on the average. 
(c) Errors due to the possibility that the smallest fibers 
were not stained, and consequently not seen. The fact that 
my count gives aresult 60% greater than STILLING’s result 
seems to me good evidence that the smallest fibers were in- 
cluded. Again, by measurements, I found. fibers the diameter 
TABLE Te. 
Showing the Number of Nerve-Fibers Counted in the Dorsal Roots of 
the Left Spinal Nerves of Man. 
Number of Nerve Number of Nerve 
No. of Spinal Area of Roots Fibers in Each Fibers in thousands 
Segments in sq. mm. Root per sq. mm. 
I 13 1808 13.6 
II 2.33 28375 12.2 
S gin! 2A 27119 12.6 
ps IV 2.01 27102 13.4 
fe Vv 2.82 28204 10.0 
oe) VI 4.65 46549 10.0 
Vil 4.72 50278 10.6 
VIII Salat 50173 9.8 
I 1.79 17891 10.0 
II 97 13432 13.7 
Ill .98 11701 11.9 
IV -90 11375 12.5 
5 Vv .68 8352 ne 
s ae 59 7155 TIE 
2 -95 12325 12.5 
ae VIII sii 8983 12.6 
IX 67 8163 12.1 
x .S6 10612 12.3 
XI -gI 11403 12.4 
XII £.25 14125 11.4 
a I 1,75 18861 10.8 
= II 2522 23640 10.6 
g III 2.53 31328 12.3 
5 LY, 2.93 39653 13.5 
Vv 3.20 43128 13.4 
I 3-44 47461 13.8 
3 II 1.92 25545 ies 
g Ill 1.18 17322 14.9 
n IV .40 $580 21.3 
Vv ai 2223 19.3 
8 
5 I 03 761 16.0 
Totals 31 54.93 653,027 11.9 
