248 The Animal Mind 



body, to wit, the following : rubbing it off against the 

 ground, shaking it off by holding the arm aloft and waving 

 it pendulum-wise in the air, holding the tube against the 

 ground with a neighboring arm and pulling the afflicted 

 arm out, pressing other arms against the tube and pushing 

 it off, and, finally, as a last resort, amputating the arm. 

 This, says Preyer, is intelligence, for the emergency is not one 

 normal to the animal, and it is adapting itself to new con- 

 ditions (617). It would, however, be demanding too much 

 even from intelligence to suppose that the starfish's behavior 

 is entirely new. A human being, capable of ideas, could 

 only, in a similar predicament, " think of," that is, call up, 

 ideas of the behavior which on former occasions somewhat 

 resembling the present had proved effective. Do such 

 cases of the trial of different devices indicate that the 

 animal concerned calls up any kind of idea or image of each 

 device before putting it into practice? Decided evidence 

 in favor of such a supposition might be furnished if the 

 "trial and error" needed to be gone through with only 

 once. A human being brought into such conditions and 

 guiding his conduct by ideas would, if placed in a similar 

 emergency soon afterwards, immediately recall the idea 

 of the successful action and waste no time over the un- 

 successful ones. But we have no reason to think that such 

 is the fact with our primitive animals. Preyer's starfish, 

 when confined by large flat-headed pins driven into the 

 board on which it lay, close up in the angles between its 

 arms, managed to escape by trying a large variety of move- 

 ments, and gradually diminished, Preyer says, the num- 

 ber of useless movements made in successive experiments 

 (617). O. C. Glaser, on the other hand, found that 

 the echinoderm Ophiura brevispina does not improve 

 at all with practice in removing obstructions from its 



