DonaLpson AND Davis, Human Spinal Cord. 23 
amined, it will be best to state what is already known concern- 
ing the length of the human spinal cord. 
The correlation in development between the medulla 
spinalis and the columna vertebralis indicates that the longer col- 
umna vertebralis would contain the longer medulla spinalis. 
The observations of RAVENEL (7) on the length of the adult 
human spinal cord, show in 11 adult males, a range in length 
of 390-480 mm., with an average of 448 mm. In 11 adult fe- 
males, the range is from 370-460 mm., with an average of 413 
mm. _ These results plainly exhibit the greater average length 
of the medulla spinalis in the male. The measurements were 
made on fresh material from the level of the upper edge of the 
atlas to the lowest filum of the coccygeal nerve on the conus 
medullaris. 
The cords examined for the length of the segments in the 
present investigation give the following lengths: 
TABLE II. 
Cord Sex Length in mm. 
WwW Male 458 
Xx ? 403 
Y ? 453 
Z Male 448 
Average, 440.5 
It is thus seen that this average length lies between the av- 
erage length for the males and that for the females, though 
rather nearer the former, as determined by Ravenet (7). It 
concerns us here, however, merely to show that the average 
length obtained is a medium one—differences according to sex 
being disregarded. The average lengths of the segments deter- 
mined from the several cords (W, X, Y, Z) are presented in 
Table I. | When these average lengths are summed, they give 
441.6 mm., for the length of the cord, against 440.5 mm., as 
determined by direct measurements. The former number is 
the one employed in the construction of the chart. 
LUperiTz (6) is the only investigator who has made a de- 
tailed study of the length of the segments of the spinal cord. 
On comparing the results just given (Table I), with those 
