SIZE CHANGES IN NERVE CELL BODIES oD 
themselves may be used. The relative volumes as parallelo- 
pipeds thus obtained are set forth in table 3. 
The cell volume less the nuclear volume gives the plasma vol- 
ume. The plasma volume divided by the nuclear volume gives 
the nucleus-plasma coefficient—the size factor of nucleus to 
plasma. The area relations of nucleus and plasma were also com- 
puted. The plasma volumes are not stated, but the nucleus- 
plasma coefficients appear in table 3. 
Between the area method and the diameter method a third 
combination is possible. The planimeter gives the area of a 
roughly elliptical median plane of the cell. Multiplying this 
area in each stage set by the corresponding transverse diameter 
of the cell and nucleus gives another set of data of relative vol- 
umes. This merely represents the volume as contained within 
a cylindrical surface instead of a parallelopiped, and the differ- 
ences are in proportion, but there was a curiosity to see how it 
would work out. These figures are the middle set in table 3. 
A graphic representation of the data of volumes and nucleus- 
plasma coefficients gives the most convenient basis for technical 
comparison. Instead however of publishing the three sets each 
of size (area and volume) and nucleus-plasma curves from each 
animal, only the three size curves of the control after the three 
methods (fig. 2) and the three nucleus-plasma curves of the exer- 
cised one (fig. 3) are presented. A reference to table 3 will show 
that the trend of the counterpart figures is identical in the two 
cases. 
The reduction of the area and volume figures for charting 
was made in terms of the ratio of the resting cell body to its nu- 
cleus. That is, in the case of the area figures, the ratio of stage 
1 is 5.3 : 1; the whole series of cell areas was divided by 5.3, the 
nuclear figures by 1. This procedure has the value of making 
the curves represent not only absolute size in the ordinates for 
each stage, as would be obtained by any convenient divisor, but 
also of giving the relative size of each succeeding stage to stage 1. 
Further, since this procedure makes the cell and nucleus start 
from the same height of ordinate, the shifts of relation between 
cell body and nucleus for each stage are shown. It gives in assc- © 
