DonaLpson AND Davis, Human Spinal Cord. re 
lengths of the segments of the spinal cord. The measurements 
of these lengths recorded by STILLING (3, p. 619), are insuffi- 
cient, having been made between the uppermost and lowest 
fila of each nerve—thus omitting some of the cord, where, as is 
conspicuously the case in the thoracic region, the line of roots 
is not continuous. A number of fresh observations were there- 
fore made. The measurements to determine the lengths of the 
segments in the adult human cord were made on one specimen 
(W)—preserved in normal size in 10 per cent. formalin;—on the 
two careful delineations (X, Y) published by Kany (4), and on 
the photolithographic chart (Z) of RipINGER (5). In the three 
plates the cord is depicted in natural size. The cords in the 
order named, are designated W, X, Y, Z. 
In the cord W, the condition of the specimen did not per- 
mit the measurement of the first four cervical segments. In 
cords X and Y, the first cervical segment could not be mea- 
sured on the dorsal aspect nor on the coccygeal segment at all. 
In cord Z, measurements on the dorsal aspect alone could be 
made, and even these could not be extended below the level of 
the 12th thoracic segment. 
To determine the length of a segment, the distance be- 
tween the uppermost fila of successive nerves was found, begin- 
ning with the uppermost filum of the first cervical nerve.' This 
was done both on the dorsal and ventral aspects of the cord. 
In making the measurements, the distance was marked off with 
a pair of spring compasses, and then this distance was measured 
on a metal scale to the nearest tenth of a millimeter. Each 
measurement has been separately entered in Table I. 
1This method of measurement credits to any segment the entire ‘‘inter- 
segmental space’’ which lies caudad to it. The method of LUDERITZ (6) was 
to credit to any segment one-half the length of the intersegmental spaces lying on 
either side of it. The difference in the results would be the amount by which, 
in any instance, the intersegmental space caudad to the part of the segment to 
which the roots were attached differed in length from the sum of half the inter- 
segmental spaces above and below the same parts. This difference in general 
would be small. 
