Protoplasmic Streaming — Relation to Gel Structure 137 



Fig. 4. The solation effect of pressure in the cells of Elodea canadensis. Lieaves 

 A and B were centrifuged simultaneously for 45 seconds, A at 6,000 Ibs./in." and 

 B at atmospheric pressure. The greater fluidity of A is indicated by the marked 

 sedimentation of the chloroplasts. Leaf C was centrifuged for 4 minutes at 

 atmospheric pressure. 



in atmospheric specimens, but only by prolonged centrifugation 

 (about 5 minutes; see Fig. 4-C) . 



When a leaf is placed in the control, and in the experimental 

 section of the centrifuge-pressure head, care must be taken that the 

 axis of the leaf is fixed in the proper position, i. e., parallel to the 

 radius of the head. Thus the displacement of the chloroplasts and 

 other heavier granules is toward one of the ends of the elongate cells, 



