228 MR. 8. LE M. MOORE’S STUDIES 
on one hand, and friction and inertia on the other. It is obvious 
that at the corners of rectangular and in the arms of meso- 
phyll cells the friction will be at its maximum; the consequence 
of this is that the grains in the arms or corners will be caught 
up by their successors, and, being impinged upon by the latter, 
a loss of momentum will ensue; and as the inertia of the massing 
grains is a constantly increasing quantity, it is clear that the 
retarding influences are ever becoming greater, so that a time 
must arrive when the energy accumulated in the protoplasm is 
no longer capable of setting the heaped masses in motion. 
Suppose, now, the chlorophyll to have undergone negative 
apostrophization. This has already been referred to recovery 
from the strain imposed by epistrophization, but massing in the 
dark seems due to another agency. We know that the epistro- 
phic interval is curtailed towards the right by any condition 
tending to depress the vitality of protoplasm; it has also been 
insisted on that the motile effects of light do not immediately 
disappear when a plant is placed in darkness; nay, that they may 
remain evident for weeks. Lowering of the vitality of protoplasm 
is therefore accompanied by increase in its sensitiveness to light; 
if this lowering take place before the motile effects of light have 
soaked out, the protoplasm is acted upon precisely as if, while 
retaining its normal vitality, it were exposed to apostrophizing 
grades of illumination. It is claimed that darkness exerts the 
required lowering effect upon protoplasm; and, if this view be 
correct, and it will, perhaps, be considered no extravagant hypo- 
thesis, there is ample justification for the surmise that, if the 
. movements of epi- and apostrophization concern protoplasm alone, 
the apostrophized grains would, for the same reason and by the 
same means which have already been mentioned as coming into 
play in respect of positive effects, mass in the corners and arms 
of their cells. 
The position here taken up is selected for the following con- 
sideration. If it be held that lowering of the protoplasmic tone 
is the sole reason for negative apostrophization, it seems difficult, 
if not impossible, to believe that there can be the required dif- 
ference in this respect between aerophytes and aquatics, while, 
if simple relaxation from tension be the sole cause, the chloro- 
phyll having been negatively apostrophized should, instead of 
massing, remain uniformly distributed upon the lateral walls. 
The latter condition is found in Funaria hygrometrica, the grains 
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