28 JOURNAL OF COMPARATIVE NEUROLOGY. 
Between the two intumescentiae of the cord, the segment 
with the smallest volume of gray substance (T III) contains 141 
cubic millimeters, which is more than half that in the largest 
segment, C VI, which contains 275 cubic millimeters. 
This shows first, that there is much less difference in the 
total amount of gray substance in the successive segments of 
the spinal cord, than would appear by comparison of the areas 
of their cross sections alone (see composite curve in Chart 1); 
second, that as a matter of fact, it is the cervical enlargement 
which contains the greatest volume of gray substance although 
the area of the gray reaches its maximum in the lumbo-sacral 
region. It may not be out of place to again call attention to 
the fact that the division of the base line into equal intervals 
for the successive segments of the cord, as in the charts based 
on WOROSCHILOFF’S curves, gives a set of relations which are 
misleading ; for it necessarily suggests that the volumes of the 
segments are proportional to the areas of their cross sections. 
Cc. RELATION BETWEEN THE AREA OF THE CROSS SECTION OF 
EACH SEGMENT OF THE CORD OR THE VOLUME OF GRAY MAT- 
TER IN IT, AND THE AREA OF THE CROSS SECTION OF ALL THE 
NERVE ROOTS BELONGING TO THE SEGMENT. 
LUpERITz (6), p. 478, has published a chart based on 
STILLING’S measurements, which shows the relations between 
the combined areas of the cross sections of each of the 
four spinal nerve roots, and that of the _ cross 
section of the gray substance of the segment to 
to which they belong. The two curves representing the two 
series of areas run nearly parallel to one another. The data, 
however, on which the curves are based, are not exactly com- 
parable, for a reference to STILLING (p. 392), shows that the 
areas of the cross sections of the nerves were taken from mea- 
surements in the case of a woman of 26 years; whereas the 
areas for the cross sections of the gray matter of the cord were 
from a five-year old child. | We have drawn a second curve in 
which the areas of the gray matter for the mature cord as rep- 
resented in Table VI, are used. This curve does not fit quite 
