SIZE CHANGES IN NERVE CELL BODIES 303 
So, can one pick up any animal regardless of its individual 
existence, and use it as a control, expecting that it give neces- 
sarily a flat level of comparison against other animals of differ- 
ent habit, different experience? The true standard exists in the 
resting cell, a distinct morphological type, a constant species 
type (Dolley, ‘14). The only exact comparison between two 
individuals is in terms of the relative distribution of working to 
resting cells. Unless one recognize this, he will surely become 
involved in a maze of discrepancies. 
It now only remains to explain why Kocher failed to find 
quantitative differences, as already noted in the citation, to nul- 
lify his criticism entirely. 
Kocher made differential counts of the distribution of the 
stages in four dogs, one the undisturbed control, the others exer- 
cised one, two and a half, and five hours respectively. He says: 
‘As will be seen in the table, the number of a particular type 
of cell varies considerably, but this variation is the same for the 
different animals.’’? The understood conclusion is that all were 
on the same plane, even granting the existence of morphological 
types. 
On scrutinizing Kocher’s table 3, one is immediately struck by 
what may be a most significant point. Stage 6 stands conspic- 
uous by its paucity, if not absence. Taking the counts from 
the worm of the cerebellum, he found none in the control ani- 
mal, though identifying all succeeding stages. In forced ac- 
tivity, the greatest number thus identified was 2 out of 300 cells 
surveyed, while in the hardest worked animal none was found. 
Nor in the cord counts is he more liberal, three being the maxi- 
mum found. Of course, in actual counts of 200 cells in a survey 
of 300, this may happen, but from my experience it is not so 
uniformly lkely. The average run of stage 6, where all types 
are present, has been from 4 per cent to 10 per cent. For ex- 
ample, in the first series of counts published (‘09 ¢), there was 
a& maximum of 67 out of 600 cells actually counted (11 per cent), 
after six hours of exercise, 40 (6.6 per cent) after one hour, and 
a& minimum of 25 (4 per cent), in a relatively very resistant dog 
in the effect displayed. A failure to identify stage 6 would dis- 
