26 JoURNAL OF COMPARATIVE NEUROLOGY. 
ING may give a somewhat greater area than would appear in 
the fresh cord. 
Although the exact effect of STILLING’s treatment has yet 
to be determined, it is not to be anticipated that more than a 
small correction will need to be made for it, and as the several 
cords used were all treated by the same method, they are com- 
parable among themselves. 
In accordance with the measurements of STILLING, three 
curves were constructed for each individual. These curves rep- 
resent his determinations for the total areas of each section, as 
well as the areas of the white and the gray substance, taken 
separately ; all measured at the most caudal level of each segment. 
To obtain a general expression for these several measure- 
ments, a composite curve—the first on the chart—was made 
from the averages of the four individual records. 
This composite curve shows the maximal total area of the 
cord to occur at the VI cervical segment, the next greatest areas 
being at the III lumbar and V Lumbar, a result dependent on the 
large area of the white substance in C VI, of both gray and 
white in L III; and of the gray in L. V. 
B. ON THE VOLUME OF GRAY MATTER IN THE SEVERAL SEGMENTS 
OF THE CORD. 
A special feature of this chart as now plotted, is that it 
enables us to estimate the volume of gray substance belonging 
to the several segments. This volume was determined as fol- 
lows: 
For the first segment we multiply the number of square 
millimeters represented by the ordinate, by the number of mil- 
limeters representing the length of the segment. In the case 
of the first segment of the cord, the result is probably a trifle 
too large. Below the first, we can make a more accurate de- 
termination of the volumes by using to represent the area one- 
half of the sum of the two ordinates limiting each segment; this 
area being multiplied by the length of the segment intervening. 
Working in this way, the following results have been obtained 
for the average volumes of gray substance in the segments of 
the cord as exhibited in the composite curve on Chart I. 
