Jennings, Behavior of Paraineciiim. 493 



gradually extending toward the anode end, until with a strong 

 current it affects almost or quite the entire body. Without this 

 second factor, the reaction to the electric current would appar- 

 ently take place in the same way as the reaction to gravity or 

 to currents of water. The first factor mentioned corresponds 

 to Pearl's "reflex factor," the second to his "forced movement 

 factor." 



Thus in the reaction to the electric current the point espe- 

 cially demanding explanation is the cathodic reversal of the 

 cilia ; it is this which distinguishes this reaction from all others. 

 As Statkewitsch (1903, a, p. 79) has emphasized, "the reac- 

 tion of the cilia is the first and fundamental phenomenon of 

 galvanotropism." Any theory of the reaction to the electric 

 current is of value just in so far as it promises to aid us in under- 

 standing the peculiar action of the current on the cilia. Theo- 

 ries which attempt to account for electrotaxis on certain general 

 considerations, without taking into account the effect on the 

 cilia, are at the present time anachronisms; they close their 

 eyes to the real problem that needs solution. 



As to the fundamental nature of the change in the proto- 

 plasm that induces the cathodic reversal of the cilia, which 

 forms the distinctive feature of the reaction to the electric cur- 

 rent, the conclusions drawn from the thorough and extensive 

 work of Statkewitsch (1903, a) are most worthy of consid- 

 eration. For details reference must be made to the original 

 work of Statkewitsch ;^ we may say here that the author 

 comes to the conclusion, after extensive experimentation as to 

 the chemical and physical effects of the electric current on the 

 organisms, that the current disturbs the usual equilibrium of 

 the processes of metabolism in such a way as to produce a change 

 in the normal backward stroke of the cilia, in the manner de- 

 scribed above (/. c, p. 158)- — this change beginning at the 

 cathode end, and progressing, as the current is made stronger, 

 over the entire body. 



' A German translation of parts ol Statkewitsch's Russian text is to ap- 

 pear, I understand, in Verworn's Zeitschrift filr Allgemeine Physiologie. 



