SIZE CHANGES IN NERVE CELL BODIES oul 
ing on such a basis the existence of functional size changes. 
For the inconstancies, take the control data: The average area 
of thes mallest cell, stage 5’—and the average covers its own varia- 
tions—is 14.57, that of the largest is 27.72 or nearly double; 
the average volume of the smallest cell is 70.44, that of the 
largest 200 or nearly triple the size. In the exercised animal 
with the still larger stage 11, the largest volume is nearly quad- 
ruple the smallest, and its area again more than double. Is it 
not apparent to any one that if such widely variant sizes or areas 
are averaged, the result depends upon the particular distribu- 
tion of types and that a wide range of results is possible? I, 
out of 20 cells, even in area computation, 5 measure 14 sq. cm. 
and 15 measure 27, the average is 24, whereas if 15 measure 14, 
and 5 measure 27, the average is 17 sq. em. The results may 
or may not prove anything about the immediate functional state. 
One can then with fair probability explain what did happen in 
Kocher’s case. He finds only small variations in average area 
size between control and exercised animals and these not con- 
stant. So far as different functioning stages appear, they tend 
to be distributed rather than bunched. <A general average, taking 
into account the smaller range of variation of area figures, would 
tend to equalize the differences due to unequal distribution of 
various-sized types. 
So Kocher, having smoothed out individual cell variations by 
averaging, found no great difference between an animal and its 
control. His results are just what might be expected in prob- 
ably the majority of cases, and instead of confounding the writer 
in respect to functional size changes, tend only to support the 
induction previously stated of a uniformity of cell size as a gen- 
eral rule for a species. Were it not for this tendency to equality 
of size of corresponding cells, collective averaging would not have 
afforded so many positive results as it has. 
Since the method of collective averaging is the one which has 
been always used, how about such results as those of Hodge? 
Are they discredited? No, but they must be qualified. Hodge 
found a smaller size in the stimulated spinal ganglion as com- 
pared with the unstimulated simply because there were enough 
