Hata, Spinal Ganghon Cells in the Rat. 17 
Harvesty has shown that in the frog it is the very small 
nerve fibers which represent those which are growing, while 
observations based on the Gotci method show that in the spinal 
ganglia as a rule the size of the cell process is proportional to 
the size of cell-body, a larger cell-body sending off a larger 
process. 
Dr. Donatpson' obtained the following results from his 
observations which were made upon growing nerve cells in the 
white rat, as they appear between birth and maturity. He says 
that ‘‘in the growing spinal ganglion of the lumbar nerves, the 
increase in volume of the largest ganglion cell-bodies was shown 
to be very closely correlated with the increase in the area of a 
cross section of the nerve fiber growing out of these cell- 
bodies.”” The following table shows the relations just men- 
tioned more in detail: 
TABLE I1V—The relative volumes of the cell bodies and areas of the cross 
section of the nerve fibers of the growing white rat of different weights— 
After DONALDSON. 
Body weight |Volumes of gan-| Areas Areas axis 
grams glion cells axis and sheath 
4-7 1.0 1.0 1.0 
10.4 1.6 1.4 2.8 
25.7 4.9 4.6 9.3 
68.5 11.2 12.2 24.0 
159.0 15.0 14.4 29.7 
From the above table, it is evident that the larger sized 
cell-body sends off larger sized processes, and smaller cells 
the smaller processes. . 
No author has ever counted the smaller and larger gang- 
lion cells separately. HaRrprEsTy’ gave the table showing separ- 
ately the number of small and large fibers forming the dorsal 
and ventral roots. This gives a general idea concerning the 
numerical relations between small and large cells in the frog. 
1 Donatpson, H. H.—The Functional’ Significance of the Size and Shape 
of the Neurone. /ournal of Mental and Nervous Disease, Oct., 1900. 
2 HARDESTY, I,—Loc. cit. 
