1 9 20] SEIFRIZ—PROTOPLA SM 



37i 



endoplasm, the outer more viscous ectoplasm, and the peripheral 

 highly viscous protoplasmic membrane. 9 



The flowing endosarc of an active Amoeba is of slightly viscous 

 consistency (v.v. 4). When quiescent, the endoplasm becomes of 

 a rather or even a decidedly viscous density (v.v. 5 or 6), but 

 seldom higher, never in the living condition attaining a gel con- 

 sistency (encystment would probably be an exception to this). 

 Brownian movement of particles is generally present and very 

 pronounced throughout the endoplasm of an active Amoeba. This 

 suggests a liquid condition. In the quiescent protoplasm of an 

 inactive Amoeba the number of particles exhibiting Brownian 

 movement is decidedly less and the amplitude of vibration is 

 reduced, which are evidences of an increased viscosity. The 

 viscosity of the ectosarc is much higher than that of the endosarc, 

 and, as in the latter, varies inversely with activity. The most pro- 

 nounced decrease in consistency of the ectoplasm occurs in the 

 region immediately concerned in pseudopodium formation, that 

 is, at the tip of an advancing pseudopodium. Here, in a rather 

 restricted center, the ectoplasm becomes quite liquid, which 

 condition, of course, is conducive to the making of a pseudopodium. 

 The liquid condition is temporary and brief. The ectoplasm not 

 directly taking part in amoeboid movement is of very viscous 



consistency (v.v. 8). 



Investigators generally recognize the high viscosity of the 

 ectosarc of Amoeba. For example, Jennings (14) says that the 

 ectosarc shows "the characteristics of matter in the solid state of 

 aggregation/' and Hyman (13) concludes that the ectoplasm is a 

 gel, "semi-rigid and more or less solidified/' The latter, how- 

 ever, although recognizing the possibility of "real fluidity" of the 

 surface layer," goes too far when assuming that the ectoplasm 

 may attain "extreme solidity." This conclusion is apparently 

 based in part on Kite's (15) statement that "little difficulty is 

 experienced in cutting it (the ectoplasm of Proteus) into pieces as 

 small as the limit of microscopical visibility." Here (as in the 



9 Some observers would restrict this differentiation to two regions, not recogniz- 

 ing a distinct protoplasmic membrane. 



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