534 HENRY H. DONALDSON AND G. NAGASAKA 
the myelin sheath which encloses it. To this point we shall 
return later. . 
Passing to the ganglion cells, the measurements obtained for 
groups of the ten largest cells in a single longitudinal section 
in each of twelve albino rats (the same rats that furnished the 
nerve fibers for table 2) are given in table 3. 
The first column gives the long diameter, the second the short 
diameter, and the third column the ‘computed diameter,’ i.e., 
TABLE 3 
Mean diameters in micra of the ten largest spinal ganglion cells in the seventh cervical 
ganglion. Long diameter, short diameter, and the ‘computed diameter’—which 
is the square root of the product of the long and short diameters. Also the mean 
diameters of the respective nuclei. The ratio of the last to the first entry is given 
at the foot of each column 
_CELL BODY 
BODY WEIGHT SERIA 
Long diameter Short diameter neue’ Mer 
grams ' 
18.7 26.4 17.6 21.6 10.6 
25.0 29.2 18.4 232 10.8 
43.3 Sane 19.8 25.6 14.4 
59.2 35.2 19.8 29.1 14.8 
81.0 36.0 24.0 29.4 15.2 
ayer 36.8 25.6 30.8 14.4 
120.3 36.6 28 .4 S2E2 1592 
149.3 38.4 30.0 33.9 16.0 
178.0 39.2 29.8 34.2 16.4 
233.1 40.4 34.4 Bf 2 18.2 
243.1 41.6 ae 39.4 18.0 
316.3 41.8 34.0 BY 17.8 
Ratios.cn 4-88 iB ES 11.9 1 28 UE EZ 
the square root of their products. These last values approximate 
the mean diameters of the cells. . Finally, the last column in the 
table gives the diameters of the nuclei. 
Determining the ratios for the last two columns, it appears 
that the spinal ganglion cells have increased 1.8 times in diam- 
eter and the nuclei 1.7 times. This increase is considerable, but 
somewhat less than that of the dorsal root fibers or of the fibers 
just distal to the ganglion. 
