332 
Mot tier. — The Effect of 
In the longer daughter-cell (#, Fig. 3), the chlorophyll- 
grains finally became uniformly distributed, when such cells 
from their pale-green colour form a striking contrast to the 
deep green of their neighbours, especially their sister-cells. 
So far as observation extended, subsequent growth in length 
seemed to be the same in both cells, i.e., the shorter did not 
increase in length more rapidly than the longer. In the 
larger cells, such as b , Fig. 3, with fewer chloroplasts, these 
bodies multiplied so that after a time the amount of chloro- 
phyll in the cell was appreciably increased. For lack of time 
the ultimate fate of these cells could not be followed. 
Centrifugal force acting transversely, i.e. at right angles 
to the longitudinal axis of the cell, caused the contents to 
collect into a band-shaped mass along the opposite side. 
After transverse displacement, redistribution required a 
relatively short time, the distance to be traversed by the 
displaced constituents being much shorter. 
Spirogyra. 
Spirogyra, being in many respects a less hardy plant than 
Cladophora , is more susceptible to injury from violent centri- 
fugal action. Specimens with tolerably large cells containing 
only one or two chlorophyll-bands were found suitable for 
experimentation. Subjected to the centrifugal action for the 
same length of time as Cladophora , a relatively large number of 
cells were badly injured, while many were killed outright. 
Consequently the time was shortened to periods of less than 
one hour. For the specimens operated with, three-fourths of 
an hour were sufficient to effect a complete longitudinal dis- 
placement of all movable contents of the cell. The cells 
to which the following paragraph refers contained but two 
chlorophyll-bands with abundant starch clustered about the 
pyrenoids. The specimens were fresh and actively growing 
with many of the cells in process of division. 
Fig. 4 represents a cell drawn immediately the preparation 
