24 _ JouRNAL OF COMPARATIVE NEUROLOGY. 
obtained by Liperirz (6), it appears that the averages of the 
sums of the segments in: his two men—33 and 37 years of age 
—show the total to be 450.5 mm., or about 2% more than the 
total sum in our case. This is a difterence which is well within 
normal limits, since the measurements of RAVENEL (7) show for 
the male cord a range in length from 390-480 mm. At the 
same time, the lengths of the segments as determined by LU- 
DERITZ, agree substantially with our own, when the differences 
in the total length of the cord and the great individual varia- 
tions in the lengths of the segments are both taken into ac- 
count. 
This can be shown by the accompanying Table (III), in 
which the percentage values of the lengths of the different 
regions of the cord as determined from our own Table (I), and 
from the observations of LUDERITZ on two male cords, are com- 
pared with the range in the lengths in these regions, as found 
by RAVENEL in II male cords. 
TABLE III. 
To show the percentage value of the lengths of the spinal cord within 
the regions named in the table, as compared with the range in 
these percentages as determined by RAVENEL. 
From Table (I) Liideritz Ravenel 
Region. 2 males, 2? 2 males, p. 460 II males, p. 348 
Cervical 21.7% 24.1% 19.8-25.0% 
Thoracic 55:8% 54-9% 53-2-65.4% 
Lumbar 13-9% 11.3% 9.1-13.6% 
Sacral and Coccygeal 4% 9.6% 1,8-15.2% 
For these reasons we are justified in employing our own 
data in marking off the abscissa for the curve showing areas, 
since, in so doing, we shall give an approximately true picture 
of the relations in the human cord of medium size. 
For the abscissa, it was decided therefore to take 441.6 
mm. and this base line was divided into lengths equal to the 
average lengths of the segments as recorded in Table I. 
Il, Areas of Cross-Sections. 
In the first instance charts were drawn life size, so to speak, 
with the abscissa 441.6 mm. long. The ordinates were drawn 
