Jennings, Reactions to Electricity. 529 



cysts at the anode. With a still stronger shock, trichocysts are dis- 

 charged also at the cathode, and at a later stage, over the whole body. 



Reaction to the Constant Current. Wallengren {3,4) studied the 

 transverse electrotaxis of Spirostomum and the anodic taxis of Opalina. 

 He finds that in both cases the current produces the same effect on 

 the cilia as in the usual cathodic taxis. The cilia of the cathode re- 

 gion are reversed, striking forward, while those of the anode region 

 strike backward. The taking of the transverse position (Spirostomum) 

 and the movement to the anode (Opalina) are due to special peculiari- 

 ties of the body structure and ciliary apparatus of the organisms. In 

 a weak current Spirostomum, and in a stronger current Opalina, go to 

 the cathode, like other Ciliata. It is evident from Wallengren's 

 work that the fundamental phenomenon in electrotaxis is the action of 

 the current on the cilia ; the direction of movement depends on more 

 or less accidental conditions. 



The work of Statkewitsch (5) is an extensive study of the reac- 

 tions of many infusoria to the electric current, as part of a general 

 examination of the reactions of animals to electricity. The work is 

 careful and thorough ; the apparatus and methods are of the best; all 

 together it is exactly such a piece of work as was needed. It is to 

 be hoped that the results may soon be published in a language that 

 will make them more generally accessible.' 



The work is filled with detailed observations of great interest ; we 

 can mention however only a few of the general results. Twenty eight 

 species of infusoria were studied, Paramecium serving as the main type 

 in the detailed description. The current was found to have the same 

 effect throughout. In the cathode region the cilia are reversed, while 

 elsewhere they strike backward, as under normal conditions. With a 

 weak current only a few cilia at the cathode tip are reversed ; as the 

 current becomes stronger the reversal spreads toward the anode end. 

 This account agrees throughout with the original one by Ludloff. 

 Thus the cathodic reversal of the cilia is the one peculiar phenomenon 

 in the reaction to the electric current. To it are due the characteris- 

 tic features of the reaction, and it is this cathodic reversal that requires 

 explanation. Statkewitsch made a thorough study of the internal 

 chemical changes due to the current, by the use of ingested 

 chemical indicators. It was found that the reaction of the endosarc 

 becomes more alkaline under the action of the current, but this is not 



'Since this review was written a summary of parts of Statkewitsch's re- 

 sults have appeared in the Zeitschrift f. Allg. Physiologic. 



