INGBERT, Dorsal Roots of Spinal Nerves. 59 
above. The measurements of each fascicle were made inside 
of the connective tissue sheath. The total area for the cross- 
section of each root is found by adding together the areas of 
its component fascicles, and is recorded in Table I*, while the 
area of each fascicle of the different roots is found in Tables 
TI-XXXII. 
4. Comparison of Areas. On comparing the areas of the 
cross-sections of the dorsal roots as determined by KOLLIKER, 
StiLLinG, and the author, and recorded in Table I? we find them 
as follows: 
KOLLIKER (male) 79.74 mm. 
STILLING (female) 57.95 mm. 
Author’s case (male) 54.93 mm. 
K6LLIKER’S areas, it is seen, are considerably larger than those 
obtained by Srituine and those by the author. This, no doubt, 
is due chiefly to the amount of connective tissue included by him 
in determining the areas from the diameters. In looking over 
my projections in Figs. 2-32 it will be evident at a glance that 
the amount of connective tissue between the fascicles is a factor 
of great importance in such a determination. 
To test the correctness of this conclusion I have deter- 
mined by KoLLIkErR’s method the area of the cross-sections of 
the dorsal roots used in my investigation. In doing this I took 
as their diameters the mean of the two diameters of the projec- 
tions. The square of the half of this diameter, i. e., the square 
of the radius multiplied by 3.1416, gives the areas of the pro- 
jections and this, in turn, divided by the square of the magnifi- 
cation of the projections, or by 68’, gives 79.14 mm’ as the 
true area of the cross-sections of all the left dorsal roots. This 
harmonizes well with KOLLIKER’s result, which was 79.74 mm? 
for the'male. The source of the difference in our ‘results ‘as 
given in Table I* is therefore evident. 
On comparing STILLING’s areas with those obtained by the 
author we again find a difference, but not so marked as that be- 
tween KO6OLLIKER’s areas and my own. Although STILiine’s 
areas are for a female and mine for a male, his are the larger. 
We again find the amount of connective tissue included to be a 
