THE VITAL PROPERTIES OF THE CELL 



107 



masses and globules being gradually taken up by the neighbouring 

 streams of protoplasm, carried along by them, and finally split up. 

 If strong shocks are repeatedly administered, so that the whole 

 cell is affected, a return to the normal condition is impossible, for 

 the protoplasmic body, by becoming partially coagulated, has been 

 transformed into turbid flakes and masses. 



In Amcebce and white blood corpuscles the streaming motions of 

 the granules and the crawling movements of the whole cell are 

 both arrested for a time by slight induction shocks; after a while 

 they are resumed and proceed in a normal fashion. If stronger 

 induction shocks are administered, the result is that the pseudo- 

 podia are quickly withdrawn, and the body contracts up into a 

 ball ; finally, very strong shocks cause the bursting and consequent 

 destruction of the contracted spherical body. 



If the induction current is applied for a considerable time to one of 

 the lower unicellular organisms, it can be gradually destroyed bit by 

 bit, and thus diminished in size. In Actinosphcerium the process is 

 as follows : the pseudopodia, which are parallel to the current, 

 soon exhibit varicosities ; they are gradually completely with- 

 drawn, whilst the protoplasm becomes massed together to form 

 little balls and spindles (Fig. 54); then at this place the surface 

 of the body becomes gradually destroyed by a process resembling 

 to a certain extent a kind of melting down, during which the 

 vacuoles, which are con- 

 tained in the protoplasm, 

 burst. On the other hand, 

 those pseudopodia which are 

 at right angles to the cur- 

 rent are unaffected. When 

 the stimulus is removed, the 

 body, which has thus been 

 reduced to about a half or a 

 third of its original size, 

 gradually recovers, and re- 

 produces the parts which 

 have been destroyed. 



The action of the constant 

 current upon the Actino- 

 sphcerium (Fig. 55), Actino- 

 phrys, Pelomyxa, and Myxomycetes, is similar to this. When the 

 circuit is closed, an excitation occurs at the positive pole or anode 



FIG. 54. Act in* sphcer ium IKclihornii, action 

 of an intern.pted current. Progressive de- 

 struction of protoplasm is equal at both poles. 

 (After Verworn, Tab. 1, Fig. 6.) 



