392 HAVE FISHES MEMORY. 



doubtful. However, I will quote from mj correspondence a few par- 

 ticularly confident statements. The more cautious lish are said fairly 

 to study the bait before they touch it, and they never allow themselves 

 to be deceived a second time, fish of prey being the only ones inclined 

 to swallow the same hook twice. Even of the latter it is reported 

 that having once been caught they grow more "careful." Several 

 correspondents report that trout which have nibbled at bait and have 

 escaped swim up to the hook, but dart awaj' from it at once, and that 

 pike whose companions have been caught wHh a fork or a net avoid 

 the net for months. It is questionable whether an observation made 

 by Roland Miiller, Mochenwangen, bears upon this point. He is in 

 the habit of fishing for trout with the yellow-gleaming minnow Devon 

 bait. At first verj^ many of them nibl)le at the bait; soon the number 

 diminishes, and he asserts that he has noticed that such as take up 

 their stand at a definite place can not be induced to bite a second time 

 in a given j^ear. Von Tschusi, of Schmitthofen, likewise reports that 

 a trout whose permanent station was well known had once been grap- 

 pled with a hook, and it refused, for a whole year, to come near a 

 hook baited in the same way. When it was finally landed with another 

 sort of bait, the thread was still in its mouth. Possibly in some of 

 these cases the explanation is that, on account of their hurt, the fish 

 refuse food altogether, and hence are not lured by the bait. In view 

 of the variety of processes that go to make up the act of food taking, 

 the conclusion is inevitable that their behavior with regard to the hook 

 indicates neither the presence nor the lack of the function of memory 

 in fishes. 



Several of my correspondents dwell upon a famous pike experiment, 

 first tried, it would seem, by Mobius. Their opinion is that the result 

 can be explained only on the hypothesis that memory exists in fish. 

 A pike in an aquarium is separated bv a pane of glass from little fish 

 which he is in the habit of eating. At first, the reports saj^, he throws 

 himself against the glass and hurts his snout. After a tmie, even 

 though the pane is removed, he makes no attempt to reach the small fry. 



This experiment is not conclusive. In the first place, I venture to 

 doubt that the pike which, guided by the organs in the lateral line, 

 avoids glass partitions with extraordinary skill, loses his cunning pre- 

 cisely in the case of a partition separating him from his food and 

 throws himself against it with such force as to bruise himself. Again, 

 a number of persons have assured me that in aquariums exposed to 

 light pike rarely attack other fish for feeding purposes. A large dealer 

 in fish here has for years been keeping pike with other fishes in the 

 aquariums in his show window without ever losing any of the latter. 

 When he feeds his pike, he must carry them down into a dark cellar. 

 If, then, in the first place, it is improbable that the experience of the 

 pike engaged in attacking his little neighbors was unpleasant, it can 



