378 



The Royal Society, London. 



The results obtained from a study of Ohara and Elodea were 

 quite consistent, but owing to the greater ease in making a quan- 

 titative determination, the latter plant was used for the more exact 

 comparative experiments. 



The action of carbon dioxide was to produce an initial slight 

 acceleration, followed speedilj by a complete cessation of move- 

 ment after disconnecting the CO2 apparatus and aspirating air 

 through the chamber the protoplasm, after the lapse of two or 

 three minutes, began to show signs of recovery. Fitful movements 

 of the granules first occurred, and then they soon resumed their 

 processional motion around the cell ; at first very slow. The mo- 

 vement rapidly became accelerated and considerably exceeded the 

 normal rate. This acceleration was not of long duration, and was 

 followed by a slowing down to the ordinary speed. 



