2O A. W. GREELEY. 



longer time, more pronounced structural changes ensue. The 

 contraction on the anodal side continues until the protoplasm at 

 this point can be seen to disintegrate, forming dense granular 

 masses, while on the opposite side the protoplasm becomes even 

 more clear and transparent than it was at first, frequently flowing 

 out over this portion of the cell in irregular liquid masses. The 

 observations have been repeated in a large number of forms so 

 that the facts of definite polar modifications in the structure of the 

 protoplasm during the passage of a weak constant current seem 

 to be very well established. At the same time it has been shown 

 in many forms that there is a movement of the protoplasmic 

 particles away from the cathodal side where liquefaction of the 

 protoplasm is taking place toward the anodal region of the cell 

 where the disintegrating or "etching" effects are shown. 1 



I have repeated these experiments and have furthermore shown 

 that when paramcecia are isolated in a weak gelatine solution or 

 held in a fine mesh-work of cotton during the passage of the 

 current so that they are unable to move freely from pole to pole, 

 a slightly different structural reaction to the current is obtained 

 after the current has been passed for from three to five hours. 

 In this case all those paramcecia which are held in the region of 

 the anode are modified as was the anodal side of the cell in the 

 preceding experiment, /. e., the whole cell contracts into a dense, 

 opaque mass of protoplasm. Likewise the paramcecia held 

 about the cathode are modified like the cathodal side of the cell 

 in the former experiment, i. e., the cell contents are liquefied and 

 there is formed a large transparent cell of fluid protoplasm which 

 ultimately bursts because of the increased pressure on the cell 

 wall. Thus we have the same structural changes occurring 

 either in the whole cell immediately about the anode, or in the 

 anodal side of any of the cells exposed to the current ; opposite 

 changes occurring in the cells about the cathode or on the catho- 

 dal side of all the cells in the preparation. 



A microscopical examination shows that these changes are 



1 Wallengren (Zeitsckr. f. allg. Physiol., 1903, III. , p. 22) states that in the Rhizo- 

 poda only can the movement of the protoplasmic particles toward the anode be demon- - 

 strated. In the Infusoria the constant current does not affect the normal streaming of 

 the protoplasm. 



