418 



GENERAL PHYSIOLOGY 



Exactly like Actinosphcerium, many marine rhizoppds, such as 

 Orbitolites, Amphistegina (Fig. 199), and others, are stimulated by 

 the making of the current to contract strongly at the anode and 

 feebly at the kathode ; this phenomenon appears much more dis- 

 tinctly and purely in long, thread-like pseudopodia than in 

 Actinosphcerium, since in the former the globules and spindles that 

 are so thoroughly characteristic of all strong excitation of contrac- 

 tion develop at the two poles especially beautifully. 1 



In the ciliated epithelia of vertebrates Kraft ('90) saw likewise 

 that upon passage of the constant current the ciliary motion was 



accelerated at both 

 poles upon making. 

 As regards the polar 

 effect of the breaking 

 he could not come to 

 any definite conclusion. 

 Finally, Loeb ('96, 4) 

 has found very recently 

 that in AmUystoma, an 

 American urodele, the 

 ~1~ cells of the cutaneous 

 glands are stimulated 

 at the anode by the 

 making of the current 

 so that a whitish secre- 

 tion is extruded at that 

 ' pole, in whatever direc- 

 tion the current is sent 

 through the body. 



Pelomyxa 2 behaves 

 somewhat differently 

 and also differently 

 from muscle. If this 

 lump of protoplasm be 

 stimulated by a con- 

 stant galvanic current, an excitation appears at the moment of 

 making only at the anode, being expressed by a sudden, jerk-like con- 

 traction followed immediately by disintegration at the anodic side 

 (Fig. 200). At the breaking of the current the same phenomenon 

 occurs upon the kathodic side, while the disintegration at the 

 anode immediately ceases. If, however, the current be kept made 

 for a long time, the body disintegrates gradually from the anodic 

 side into a dead mass. Hence, Pelomyxa shows likewise that the 

 continued constant current acts as a continued stimulus. The 

 irritability always becomes less, the longer the current remains 

 made. If, after the action has continued for some time, the current 



FIG. 199. Amphistegina tessonii. (Cf. Fig. 170, p. 378.) The 

 lenticular calcareous shell stands upon its sharp edge, and 

 from the opening, which is directed toward the ground, 

 sends in all directions thread-like pseudopodia ; upon 

 these may be clearly recognised at the anode a very strong, 

 and at the kathode a very feeble, excitation of contraction. 



1 Cf. Verworn ('92, 2). 



2 Cf. p. 400. 



