i64 BEHAVIOR OF THE LOWER ORGANISMS 



when the peristome is directed toward the cathode. When the peri- 

 stomal cilia are thus striking forward, their action is comparatively in- 

 effective, so that it does not overcome the attachment to the substratum, 

 in the contact reaction. 



3. Theories of the Reaction to Electricity 



What is the cause of the reaction to the electric current ? The most 

 striking phenomenon in a general view is usually a movement of the 

 organisms en masse toward the cathode or anode. It is well known that 

 the electric current has the property of carrying small bodies suspended 

 in a fluid toward the cathode or anode, depending on the conditions. 

 This phenomenon is commonly known as cataphoric action, or as elec- 

 trical convection. When the movement of small organisms toward one 

 of the electrodes is mentioned, the first thought that comes to mind is 

 of course the possibiKty that they are thus passively carried by the cata- 

 phoric action of the current. But this view can be maintained only bn 

 the basis of an extraordinarily superficial acquaintance with the facts. 

 Careful study shows, as we have seen, that the current has definite and 

 striking efltects on the cilia, and that it is to these effects that the peculiari- 

 ties of movement under the action of the current are due. Nevertheless, 

 the theory that the phenomena are passive movements due to the cata- 

 phoric action of the current continues to be brought gravely forward at 

 intervals, and doubtless this will continue. The fundamental fallacy 

 of this theory is the idea that we must account in some way by the action 

 of the current for the fact that the organisms move. This is quite un- 

 necessary, for they move equally without the action of the current. The 

 movement is spontaneous, so far as the electric current is concerned. It 

 takes place by the agency of the motor organs of the animal, driven by 

 internal energy, and acting upon the resistance furnished by the water. 

 It is only the changed direction of the movement that the electric cur- 

 rent must account for. There is no place for the agency of the cata- 

 phoric action in transporting the animals, for they are visibly transport- 

 ing themselves, just as they were before the cataphoric action began. 

 It is absolutely clear that the movements of the ciHa, described in the 

 preceding pages, are at the bottom of the observed behavior, and any 

 explanation of the reaction to electricity must account for the influence 

 of this agent on the cilia. This the theories of passive movement by 

 cataphoric action make no attempt to do. 



The clearest disproof of the theory that the movement is a passive 

 one due to cataphoresis is of course the well-established positive proof 

 that the movement is an active reaction of the organism. But the theory 



