The Morphology of Functional Activity in the Ganglion Cells etc. 
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resting cell. It takes place so quickly and is so early associated with 
deteriorative chauges that it is very doubtfully for the stages alter the 
initial iucrease of substance to be regarded as triie growth. At most, 
it is very slight, a property that has been lost in its highest differentiation. 
It has not only gone beyond the power of division (vegetative grovth) 
biit its power of functional growth is very restricted. But lower in the 
scale, the cell of Cambarus is a type for study which retains its power 
of functional growth in most marked degree, a distinction which is im- 
portant from the opportunities it lays clear. 
Summary. 
From the analysis of the variations in cell size and nuclear size in 
different normal animals in relation to the resting cell and of the cor- 
responding grades, fii'st of increase of substance, then later of edema 
and decrease of extra-nuclear chromatin and nucleolar substance; from 
the identical sequence of events alter experimental hyperstimulation, 
residting in forcing all cells to a more advanced state of activity and 
differing only in the extent of changes and not in the kind; and from 
the exact correspondence in essential detail of these results with those 
from the Purkinje cell of mammals, the morphological reaction to func- 
tional activity in the ganglion cells of Cambarus virilis has been determined 
as set forth in the following abstract. 
For aU ceUs, sensory and motor, there is a fixed type of resting cell 
from which activity Starts and to which subsidence from activity recm’s. 
The size changes are the predominant morphological feature in such 
primitive cells. On the side of the cytoplasm, from the resting ceU to 
the state approaching exhaustion observed, the cell body steadily and 
progressively increases in size. On the side of the nucleus, however, 
fluctuations occur. Up to a point at least double the volume of the rest- 
ing cell, the cytoplasm and nucleus increase ir exactly the same propor- 
tion, so that the nucleus-plasma relation remains a constant. After this 
point the nucleus undergoes a shrinkage, which is a primitive and limited 
Prototype of the shrinkage of both ceU body and nucleus, fust determined 
by Hodge for nerve ceUs. The nucleus-plasma relation consequently 
shifts abruptly and decidedly in favor of the cytoplasm. Succeeding 
this there is a disproportionate enlargement of the nucleus which causes 
the nucleus-plasma relation to tend in turn toward the advantage of 
the nucleus. This is the prototype of the maximum disproportion in 
favor of the nucleus at a corresponding stage determined by the writer 
