40 JOURNAL OF COMPARATIVE NEUROLOGY. 
(7) RAVENEL, M: 
Die Maasverhaltnisse der WirbelsAule und des Riickenmarkes beim 
Menschen. Zeztschrift f. Anatomie u. Entwickelungsgeschichte. Bd. il. 
1877. Pp. 334-356. 
EXPLANATION OF CHART I. 
This chart represents by curves, the areas of the cross-sections of several 
human spinal cords, as well as the areas of the gray and white substance as 
they appear in each section. The base line in all the charts is just one-third 
the length of the spinal cord for which it stands, and is divided into lengths 
proportional to those of the spinal cord segments of which it is composed. For 
the adult cord, the lengths of the segments given in Table I were used in 
making the original drawings. On the ordinates one linear millimeter corre- 
sponds to one square millimeter of area. In all cases the measurement of the 
area was made up at the caudal end of the segment. In the order from above 
downwards, the curves are as follows: 
Composite Curve—Bised on A, B, C, and D, to give the average of the 
several areas in the curves named. The curves are generalized and apply toa 
cord of medium length—441,6 cm. long. The influence of sex is neglected. 
The average age of the four cases would be 33 years. 
Curve A. Man of 45 years. Data for areas from STILLING. 
Curve B. Woman of 35 years. Data for areas from STILLING. 
Curve C. Woman of 25 years. Data for areas from STILLING. 
Curve D. Man of 25 years. Data for areas from STILLING. 
Curve E. Child—data for areas from STILLING’s observations on the 
cord of the two-year old child. Length of segments from 
LUDERITZ’s observations on the cord of a three and a half 
year old girl. Cord rather short. 
