344 
Mot tier . — The Effect of 
of the cell-cavity ; but the side next to the vacuole is probably 
more concave than it seems, in which event the displaced 
mass would present the form of a cup. Delicate strands are 
frequently seen running along the hautschicht , from which 
ramifications may penetrate the cell-lumen. Displacement 
takes place in plasmolyzed cells very much as in normal ones 
(Fig. n). This fact would seem to indicate that the density 
of the cell-sap in itself does not affect in any appreciable way 
the free movement of bodies held in the cytoplasm. Cells 
may, of course, be plasmolyzed to such a degree that all the 
chloroplasts are crowded together, when little space is left for 
displacement and when the contracted primordial utricle holds 
all inclusions firmly in a fixed position. 
In order to see what effect, if any, a difference in tempera- 
ture and illumination might have upon the redistribution of the 
cell-contents, one set of plants on being removed from the 
centrifuge was placed in a cold house at a temperature of 
2 ° C., while another was kept in the laboratory at a tempera- 
ture varying from i 6 ° to 20° C. Of those in the laboratory, 
one portion remained in diffused light, another was kept in 
darkness, and a third within a cylindrical screen of heavy 
white paper beneath an incandescent electric lamp. In cells 
exposed to the diffused light of the laboratory room at 20° C., 
redistribution was about completed in four hours and a half. 
The chloroplasts were generally arranged along those cell- 
walls which are perpendicular to the surface of the leaf. In 
those kept in darkness at the same temperature (20° C.), 
redistribution was accomplished in the same time, the orienta- 
tion of the chloroplasts being the same. Redistribution in 
the cells exposed to the electric light required about the 
same time, but here the chloroplasts were more uniformly 
distributed upon the entire inner surface of the cell. Different 
intensities of illumination, therefore, so far as observation 
extended, played no important part as a factor in the redis- 
tribution. 
Temperature, on the contrary, seemed to have much to do 
with the movement of displaced portions of the living substance 
