44 STRUCTURAL BOTANY 



quiet eddy in the stream. This still part is called 

 the indifferent land, and it is always present where 

 rotation of the protoplasm goes on. 



But even in the other parts of the cell it is not 

 really the whole protoplasm which rotates. The 

 ectoplasm that is, the thin outer layer in immediate 

 contact with the cell-wall remains stationary, while 

 the revolving endoplasm (containing the chlorophyll 

 granules) travels over its inner surface. 



This will serve to .represent an important type of 

 protoplasmic movement that of rotation. 



Another form of movement may often be observed 

 in the broader cells of the lamina of the Elodea leaf 

 see Fig. 19). Here the vacuole of the cell is 

 traversed by strands of protoplasm, most of which are 

 attached to the nucleus, which is here suspended in 

 the cavity of the cell. In these cells the protoplasm 

 is in active movement in all directions. The strands 

 crossing the cavity show active currents by which 

 chlorophyll granules are often swept along. In the 

 thicker strands there may be two opposite currents 

 flowing simultaneously. The protoplasm lining the 

 cell-wall is also in movement, but not as in the first 

 case all in one direction, for here there are varying 

 streams running in different directions in different 

 parts of the layer. Neither the arrangement nor the 

 direction of movement of the protoplasm is constant. 

 Sometimes a protoplasmic strand is snapped in two, 

 and both halves drawn back into the main mass. 

 Sometimes a new strand is put out, which extends 

 itself across the vacuole and joins on to the proto 



