312 



MOTOR RESPONSES 



various sizes. The latter are filled with hyaline substance containing a 

 few scattered granules which exhibit violent Brownian movement, show- 

 ing that the substance in which they are suspended is a fluid with low 

 viscosity. Some of the folds and papillae round up and pinch off, to 



Figure 114. A series of camera sketches of an Amoeba, showing the effect of an 

 alternating current. A, before current was made; B-F, successive stages after it was 

 made; g, plasmagel ; s, plasmasol; /, plasmalemma; h, hyahne layer; c, hyaline cap; 

 arrows, direction of streaming; double headed arrows, direction of the current. Note 

 that the Amoeba orients perpendicularly to the direction of the current, that the plasmagel 

 in the pseudopods is at this time very thin or absent, that the plasmagel contracts violently 

 at the surface directed toward the poles, that blisters are formed on these surfaces, and 

 that the Amoeba eventually breaks here and then disintegrates. If the surrounding medium 

 is acid, the Amoeba does not break and disintegrate. (After Mast, 1931a.) 



form spherical bodies filled with granule-containing fluid observed in 

 the folds (Fig. 114). 



If the current is strong enough, the plasmagel usually breaks after 

 it has thus contracted. The plasmasol flows out and the entire amoeba 

 soon disintegrates and dissolves. Sometimes breaks occur in the pseudo- 



