The Morphology of Fiinctional Activity in tlie Ganglion Gells etc. 541 
The difference is obviously not one of nieclianism. Judging front 
the idcntical coiirse of the size changes, from the cxactitnde of tlie 
purpose accomplislied and the ultimate cffect as regards both chromatin 
and nucleolar snbstance, the mechanism works the same way to ac- 
complish the same resnlt. The crayfish cells, both sensory and niotor, 
afford another illnstration of the universal imity of tlie anatomical 
process nnderlying function in nerve cells wliich has been stated else- 
where (1911b). 
If not in the mechanism, the difference must lie in the materials 
through which the mechanism accomplishes its purpose. In short, it 
must be inherently Chemical. The more positive evidence of that from 
the anatomical point of view is on the side of the consumption of chro- 
matin. A more unstable, more explosive, more easily oxidizable com- 
position would adequately explain why in the more differentiated cell 
the supply so rapidly falls short in a continued deraand. It cannot be 
that here more chromatin is required to produce any given discharge 
of energy and hence disappears more quickly on strain. For example, 
taking a higher and lower cell involved in the same reflex, such as a motor 
cell of the cortex and one of the spinal cord, one cannot believe that for 
each single Stimulus the more specialized cell uses two molecules to the 
one of the other. Yet with an identical mechanism as demonstrated, 
which for the sake of illnstration will be supposed to prodnce an identical 
snbstance, this would have to be to explain the earlier exhaustion in the 
higher cell. The substances produced must differ in composition. Judging 
from the comparative States of higher and lower cells in a given physical 
overstrain, such as over-work of dogs in a treadmill, the lower cell is 
capable of independent response for a mueh longer time than at this 
two to one rate or even in much greater disproportion wonld exhaust 
its chromatin. It is the Hodge stage against exhaustion. It takes 
the cells of Cambarus weeks to arrive at what for the Purkinje cell 
its a matter of hours if continuously stiniulated. The less differen- 
tiated ceUs in the higher mammals studied have more the character- 
istics of the ceUs of Cambarus and a resistance so great that certain 
physiologists, despite the cell theory, are committed to their inexhaus- 
tibility, 
But the same Chemical differences conld be the basis as well of the 
greater sensitiveness of the nucleus requmed in composition in the higher 
cell and the earlier strain of making a more complex product would be 
expected. It then continues to make the attempt, only the materials 
are lacking. Granting the significance of the anatomical unity in me- 
