DonaLpson AND Davis, Human Spinal Cord. 37 
curve, it runs above 100 sq¢.mm. The intumescentiae are more 
abrupt. The enlargements of the areas in the intumescentiae 
as compared with the areas in the thoracic region, are greater. 
The maximum total areas in both the cervical and lumbar in- 
tumescentiae are further caudad, and the absolute area of the 
white substance is much less than at maturity. The most 
marked deficiency in the areas of both gray and white sub- 
stance occurs in the first three cervical segments, and especially 
in the third cervical segment. That this last feature is not an 
individual peculiarity, is indicated by the fact that the one year 
cord in Table VI (the only cord available for comparison) 
shows a similar relation. As the curve E is based on a single 
individual, no significance can be attached to minor peculiarities 
in it, but enough has been shown by the comparison just 
made, to indicate that the cord of the child differs from that of 
the adult in a number of its characters, and that the curves 
showing the areas in childhood cannot be properly used to 
show the relations obtaining at maturity. 
Conclusions. 
The foregoing observations warrant the following conclu- 
sions : 
The chart given in this article is more correct than that 
based on the curves of WorRoSsCHILOFF, since the areas of the 
gray and white substance are taken from measurements on the 
mature spinal cord, and are plotted on a base line, the divisions 
of which are proportional to the lengths of the spinal segments. 
These curves show the greatest areas at the level of C. 
VI, L. III, and L.V. The curves, however, are generalized, and 
apply to a cord of medium size, the differences due to sex be- 
ing disregarded. 
Moreover, the measurements of the areas are from cords 
which had been hardened in chromic acid, and preserved in al- 
cohol. This treatment has certainly altered the size of the 
cord, but control experiments indicate that the alteration in 
size has probably been slight. A study of chart I (see Table 
V) shows that the volume of gray substance in the intumescen- 
tia cervicalis is greater than that in the intumescentia lumbalis. 
