132 



The Structure oj Protoplasm 



100 5J 



90 



80 



70 



60 



= Arbitrary point; all other values 

 are relative to this. 



T =: Gel value, Amoeba. 



J. = Gel value, unfert. Arbacia egg. 



X — Gel value, cleaving. Arbacia egg. 



+ — Rate of cleavage, Arbacia egg. 



• — Gel value, Elodea cells. 



— Rate of streaming, Elodea cells. 



M — Gel value, myosin gel (rabbit) 

 pH = 65: temp. 23°-24°C. 



10 



PRESSURE -LBS./ 1 N^x 10^ 



Fig. 2. Proportionality between the effects of pressure on protoplasmic 

 streaming (and cell division) and the degree of solation imposed by pressure, 

 in various gel systems. The data for the myosin gel are entirely tentative, 

 since only points nearest the general curve were selected from several pre- 

 liminary experiments. 



gradual change in the entire form of the amoeba such that in about 

 5 minutes all of the specimens become quite spherical. 



This type of experiment clearly indicates that the tubular form 

 of a pseudopodium is maintained by rigid properties which are 

 inherent in the plasmagel layer. The data of Figure 2 reveal that 

 the rigidity of this layer at 6,500 lbs. is less than 20 per cent of its 

 atmospheric value. When the rigid properties of the gel are lost, the 

 pseudopodium behaves as a cylinder^ ^ of nonmiscible liquid sus- 

 pended in water and becomes unstable under the tensional forces of 

 the surface. 



