Animal Instincts and Tropisms 271 



that the effect of the current consists in altering the 

 tension of the muscles of the legs in such a way as to 

 make it easy for the animal to move toward the anode 



Fig. 45 



and difficult to move toward the cathode. Thus if the 

 current be sent sidewise through the animal, say from 

 left to right (Fig. 45), the legs of the left side assume the 

 flexor position, those of the right the extensor position. 

 With this position of its legs the animal can easily move 



