DIAMETERS OF NERVE CELLS AND FIBERS 543 
It is fair to assume that this maintenance of the sensory dis- 
crimination calls for an increase of histological complexity in the 
cell body, and with this we might associate the increase of size. 
In this connection it is worth noting first that if we take 
the data from table 7 and assume, as is usually done, that the 
squares of the cube roots of the body weights stand in the same 
relation as the respective surfaces of the animals compared, then 
TABLE 9 
Giving (A) the ratios of the relative body areas (squares of the cube roots of the body 
weights) of the four groups of rats and the ratios of the corresponding relative vol- 
umes (cubes of the diameters) of the spinal ganglion cells; and (B), the ratios of 
the relative body areas compared with the relative areas of the axis cylinders in the 
corresponding dorsal root fibers—as given in table 10 
(A) 
RELATIVE AREAS OF BODY RELATIVE VOLUME OF GANGLION CELLS 
Body weights, grams Ratios Can diam- Ratios 
VY 29.0? : 7/264.2? 1 Aah | 23a8) 3 Bete 1 4.26 
V 85.1? : 7/ 264.22 1 Doig |. 2O.83 = Sar 18 1 2.09 
V 149.22: 7/264.22 1 1.46 | 33.43 : 38.13 1 1.48 
V 264.22 : 7/264.22 1 1.00 | 38.13 ; 38.18 1 1.00 
RELATIVE AREAS OF AXIS CYLINDERS IN 
RELATIVE AREA F BODY 
x et 3 SQUARE MICRA 
In root fibers distal to 
ganglion at (A) 
Aer || aiden, Be. weer ie yes 
PREY | eee SET oS Be | ey: 
1.46 | 89.9 :. 134.7 1 
TROOM PUSAN (ar es 13467, 1 
oe oe os 
the first column in table 9, giving the squares of the cube roots of 
the body weights can be used to obtain a series of ratios. The 
relative area for the heaviest group is used as the standard, and 
the ratios between it and the values for the preceding groups. 
determined. 
If the first three areas are compared successively with the final 
or fourth area, there appear the ratios given in the last column 
