GALVANOTROPISM 



37 



extensor position (Fig. 4). The transverse current thus 

 makes it easy for the animal to move toward the left — 

 the anode — and prevents it from moving toward the right 

 — the cathode. If a galvanic current flows transversely 



Fig. 4. — Position of legs of shrimp when current goes sidewise through the animal, 

 from left to right. In the legs on the left side the tension of the flexors, in those of the right 

 side the tension of the extensors predominates. The animal can easily go to the left (anode), 

 but not to the right. (After Loeb and Maxwell.) 



through the animal, it creates the analogue of the circus 

 motions produced by injury of one side of the brain. 

 Figs. 5 and 6 show that the current produces similar 

 effects in the crayfish as those produced in the shrimp 

 (Figs. 2 and 3). 



