Hatai, Spenal Ganglion Cells in the Rat. 23 
ing fibers which are foundin an adult frog might, therefore, very 
well be formed by the axones of these latent cell-bodies. 
We have ventured to classify the spinal ganglion cells ina 
few groups but noticed that each group contains many varieties 
of the cells which were at first puzzling. These varieties appear 
to be the transitional stage. 
If the spinal ganglion cells, are classified according to the 
measurements of size, then would follow: 
I. Large cells (Series A and a); cells in completely ma- 
ture stages. 
II. Intermediate cells (equal in size to those in Series a 
and B); cells in both mature and immature stages. 
III. Small cells (Series Band b); cells in immature stages. 
VI. SumMarY. 
I. The spinal ganglion of the white rat contains two var- 
ieties of the cells; one variety is larger in size and stains lightly 
with eosin and erythrosin; another variety cells is smaller in 
size and stains deeply with eosin or erythrosin. 
II. Besides the above two varieties, the spinal ganglion 
of the white rat contains one more distinct variety of the cells. 
This stands as ‘‘intermediate’’ in its structure and size between 
the two former varieties. 
III. The small spinal ganglion cells which were described 
as chromophilic cells are considered by the writer as in an im- 
mature or growing condition, and not as pathological nor as arte- 
facts as has been maintained by some of the previous authors. 
1V. When the spinal ganglion cells of the white rat are 
classified according to size, into large, intermediate and small 
cells, these three groups are also found to be regularly graded 
in their internal structure. 
