50 The Animal Mind 



. . . after Amoeba b has escaped completely and is quite 

 separate from Amoeba c, the latter reverses its course and 

 recaptures b. What determines the behavior of c at this 

 point? If we can imagine all the external physical and 

 chemical conditions to remain the same, with the two 

 Amoebae in the same relative positions, but suppose at the 

 same time that Amoeba c has never had the experience of 

 possessing b, — would its action be the same ? Would it 

 reverse its movement, take in b, then return on its former 

 course ? One who sees the behavior as it occurs can hardly 

 resist the conviction that the action at this point is partly 

 determined by the change in c due to the former possession 

 of b, so that the behavior is not purely reflex" (378, p. 24). 

 If it is true that an Amoeba which had not just "had the 

 experience of possessing b" would not have reversed its 

 movement and gone after b when the latter escaped, still 

 we cannot think it possible that c's movements in so doing 

 were guided by a memory image of 6. It may be supposed 

 that the recent stimulation of contact with b had left a part 

 of c's protoplasm in a condition of heightened excitabihty, 

 so that the weak stimulus offered perhaps by sHght water 

 disturbances due to b's movements after escaping produced 

 a positive reaction, although under other circumstances no 

 reaction would have been possible. (Compare the observa- 

 tion of Schaeffer, just quoted, on Amoeba's abiHty to react 

 . to objects not in contact with it.) In any case, there is no 

 / evidence that Amoeba's behavior is influenced by stimula- 

 f tion occurring earlier than the moments just preceding 

 \ action ; no proof of the revival of a process whose original 

 \ effects have had time to die out ; and it is upon such revival 

 that the memory images which play so much part in our 

 own conscious life depend. 

 Let us consider for a moment some of the results of the 



