530 Journal of Comparative Neurology and Psychology. 



limited to either end of the body. (The longitudinal rotation of the 

 endosarc would prevent such limitation, even if the effect were primar- 

 ily produced at one end.) Statkewitsch concludes that the reversal 

 of the cathodic cilia is due to an interference with the metabolic pro- 

 cesses, showing itself in this greater alkalinity. 



Of observations on subordinate points, the following are interest- 

 ing. If the current is frequently reversed, the organisms maintain a 

 transverse position. A careful study of the contraction at the anode 

 and swelling at the cathode led to the conclusion that these could not 

 be accounted for by the direct cataphoric action, but depend on the 

 vital contractility of the protoplasm. The electric reaction was shown 

 to be independent of rheotropism. A particularly careful study was 

 made of the reactions of infusoria in solutions of chemicals. The ani- 

 mals were gradually acclimatized to the solutions, and it was then 

 found that the reaction to the electric current is the same as in ordi- 

 nary water. It is only when the infusoria are first introduced, and are 

 inclined to swim backward as a result ot the chemical stimulation, 

 that they swim in the current backward to the anode. 



As a result of his work, Statkewitsch rightly insists that "the 

 effect on the cilia is the first and fundamental phenomenon of galvan- 

 otropism." This is evident indeed from all thorough observations on 

 the subject, from those of Ludloff through the work of Pearl, Wal- 

 LENGREN and others, to this work of Statkewitsch. 



Greeley (6) attemps to bring the reaction of Paramecium to the 

 electric current in some way in relation with the electric charge which 

 he supposes the particles of protoplasm to carry. In Paramecia from 

 normal alkaline or neutral cultures he holds that the protoplasm is a 

 colloid whose particles carry a negative charge. Such a colloid is 

 liquefied by anions and by the cathodic effect of the current (that is, 

 the effect produced on the end next the cathode); coagulated by cations 

 and the anodic effect of the current. In Amoeba this would result in 

 a solidification and contraction of the anodic side, with a liquefaction, 

 decrease of surface tension, and flowing out on the cathode side ; hence 

 according to Greeley, the movement of Amoeba to the cathode. 

 How similar factors could bring about the observed movement of Par- 

 amecium to the cathode Greeley makes no attempt to show, but he 

 holds that in some way this does occur. "The ultimate determining 

 factor of the response to the electric current must be the electrical 

 condition of the protoplasm itself." The essential point in Greeley's 

 view is the following: "In every case the reaction of a Paramecium 

 to an external stimulus leads it to remain under those conditions which 



