60 JOURNAL OF COMPARATIVE NEUROLOGY. 
probable source of error. On examining the projections of the 
cross-sections of the dorsal roots in Sritiine’s Atlas (1859)”, 
Table XVIII, we find that he has divided the roots of the 31 
left spinal nerves into only 228 fascicles, while, as will be seen 
from my plates, I divided the same number of roots into 504 
fascicles. It is therefore evident that he has included in his 
results the areas of some connective tissue septa which I have 
been able to exclude. Another source of difference is the fact 
that I made corrections for fascicles cut obliquely. In doing 
this, the number of fibers in a fascicle cut obliquely was di- 
vided by the number of fibers per sq. mm. in the nearest ad- 
joining properly cut fascicle providing this had the same ap- 
pearance as regards the size and density of its fibers. By this 
means the area of the fascicle in question was reduced to the 
size of its cross-section when cut at right angles to the fibers 
composing it. In computing the total area of the nerve this 
corrected number was the one employed. Where corrections 
were made the number indicating the uncorrected area is placed 
in parenthesis in Tables II-XXXII. In the accompanying 
projections, Figs. 2-32, however, all the fascicles appear drawn 
with the area which they present in the section. But where it 
it has been necessary to make a correction in the Tables for the 
obliquity of the fibers the letter C appears within the fascicle. 
The total amount thus deducted from the apparent area of 
all the roots was 1.389 mm.” Adding this to 54.93 we get 
56.39 mm.” as the uncorrected area. If to this we could add 
the area represented by the connective tissue septa which I 
have excluded but which Sritiine included, my results would 
probably be a trifle larger than his. 
Another source of difference in the results obtained by 
K6LLIKER, STILLING, and the author is the amount of shrinkage 
caused by the reagents employed. The roots used by KoLtt- 
KER were, as before remarked, most probably.not treated with 
any reagents and should in this respect be normal. STILLING 
attributes a slight shrinkage to the tissue which he measured, 
but if this be greater or less than than the shrinkage from the 
reagents I used there is at present no means for deciding 
