DOUGLAS MARSLAND 125 



grees of weakening produce a proportionate retardation in the progress of 

 the furrows. 



Evidence is submitted which indicates that the splitting of the high 

 potential phosphate bonds of adenosine triphosphate may contribute energy 

 to the formation of the i)lasmagel structure — which is an endothermie proc- 

 ess. In any event, the furrowing reaction and the plasmagel structure are 

 both strengthened when additional ATP is provided via the surrounding 

 sea water, and weakened when mersalyl acid (salyrgan), an inhibitor of 

 ATP hydrolysis, is employed. 



Generally speaking, the data indicate that the gelation process is causally 

 related to the development of protoplasmic contractility and represents a 

 mechanism by which the cell utilizes metabolic energy in the performance 

 of mechanical work. 



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