Hata, Spznal Ganghon Cells in the Rat. 15 
the frog corresponds in these cases to from 2.45 to 3.26 of the 
spinal ganglion cells. 
BUEHLER’ obtained the following results from the examin- 
ation of ninth spinal nerve of the frog (Rana esculenta). He 
found in dorsal root 680 fibers and in the spinal ganglion about 
3500 cells giving a ratio of I to 5, while according to Lewin? 
in the 32nd spinal nerve of the rabbit there were found only 
3173 posterior root fibers to correspond to the 20361 cells of 
the spinal ganglion ; a ratio of 1:6.4. 
BirGE’ was able to show in the frog, first that the number 
of fibers found in the dorsal and the ventral spinal nerve roots 
increased as the frog increased in size, and second that in both 
the IInd and [Xth nerves there was an excess of fibers in the 
trunk over and above the sum of the fibers in the two roots. 
This excess amounted to 16% inthe case of the IInd nerve 
and 14%, for the IXth. 
Harvesty’s* studies on the spinal nerves of the frog gave 
us some important results. He summarized his observations 
as follows: 
“rt, The number of fibers in the ventral roots decreases 
from the spinal cord toward the spinal ganglion. 
‘‘2, The number oj fibers in the dorsal roots decreases 
from the spinal ganglion toward the spinal cord. 
‘4. The section of the nerve trunk immediately distal 
to the spinal ganglion (dorsal branches excluded) contains a 
1 BUEHLER, A.—Untersuchungen iiber den Bau der Nervenzellen. Ver- 
handlungen der Fhystk.-med. Gesellschaft zu Wiirzbu:g. N.¥. Bd. 31, p. 285, ’98. 
? LEWIN, VON TH.—Ueber die Zahlen der Nervenfasern und Ganglienzellen 
in den Spinal Ganglien des Kaninchens. Centradldl. fiir Physiologie, ’96, Heft 
15 und 16. 
3 BirGE, E. A.—Die Zahl der Nervenfasern und der motorischen Ganglien- 
zellen im Riickenmark des Frosches. Archiv fiir Anatomie und Physiologie. 
Physiologische AbtheiJung. H. 5 und 6, 1882. 
4 Harpesty, I.—The Number and Arrangement of the Fibers forming the 
Spinal Nerves of the Frog (Rana virescens). /. of Comp. Neurol., Vol. IX, 
No, 2, ’99. 
