6 JourNAL oF ComPARATIVE NEUROLOGY. 
same size as those in Series B, but never being found as large 
as those in Series A or as small as those in Series b. 
This material, taken from the white rat with a body weight 
of 140 grams was fixed with formalin-acetic-sublimate mixture 
(6) and stained by toluidin blue and erythrosin. 
As is shown in Table I the size of the cell-bodies is vari- 
able; the smallest have neariy the same size as in a young rat 
just after birth, but the largest ones attain nearly three times 
their diameter. These measurements of spinal ganglion cells 
in the white rat correspond to those obtained by other in- 
vestigators in this laboratory. Between these extremes, many 
cells intermediate in size are noticeable. Before going on to 
discuss the peculiarities of these cells, it may be well to com- 
pare the diameters of the spinal ganglion cells in other verte- 
brates with those in the white rat. 7 
BuEHLER' measured the spinal ganglion cells in several 
classes of vertebrates. He obtained the following results : 
TaBLE I]—Showing the diameter in yz of spinal ganglion cells in various 
vertebrates—after BUEHLER. 
First column gives the average diameter. 
Second ‘ he ‘* diameter of the largest cells. 
Rhard: 7 <5 che . ce pL smallest cells. 
Name Average Largest Smallest 
Fish (Leuciscus 
rutilis) 14 cm | 
long 20 30 10 
Frog 40-50 70-80 10-20 
Lizard 25 20 
Dove 30-40 50 12-20 
Cat 50+ 70-80 22 
Rabbit 50+ 70-80 16 
Dog 50+ 108 24 
Man 45-67 120 20 
He also noticed that the spinal ganglion contains a greater 
number of small than of large cells. 
CavaAZzANNI also measured the diameters of spinal ganglion 
1 BUEHLER, A.— Untersuchungen iiber den Bau der Nervenzellen. Wiirz- 
burg, ’98. 
2 CAVAZANNI, E.—Sur les Ganglion Spinaux. “Arch. Ital. de Biologie, 
T. xxviii. 
