314 GENERAL ZOOLOGY 



the effect which had invariably followed a movement in the 

 direction of the minnows. On the whole, the observer con- 

 cluded that the perch showed strong symptoms of having 

 learned to appreciate the presence of an obstacle, for neither 

 fish made a move in the direction of the minnows when the 

 partition was first removed. The same observer noted that 

 perch are very imitative, a series of motions on the part of 

 one being very likely to be performed by others. This is prob- 

 ably of use in connection with their gregarious life, where 

 the " school " is kept together by each fish watching and fol- 

 lowing the others. 



Sight is probably the best developed sense, though, as 

 already stated, the eyes are not adapted to vision at a great 

 distance. To test the power of sight discrimination, the ob- 

 server quoted above dropped into the aquarium pieces of 

 wireworms (larvae of click-beetles) alternately with similar bits 

 of earthworms. Nearly every time one or more of the bits 

 of wireworm were seized by the perch, only to be dropped 

 a moment later. The fishes did not seem to make any per- 

 manent association between the appearance of the wireworm 

 and its inedible character. 



Perhaps the clearest way to picture the limitations in 

 the mental organization of a fish is to sum up, as Professor 

 Sanford does, some characters in which the fish differs from 

 man. "No fish is ever conscious of himself; he never thinks 

 of himself as doing this or that, or feeling in this way or that 

 way. The whole direction of his mind is outward. He has 

 no language and so cannot think in verbal terms ; he never 

 names anything ; he never talks to himself. As Huxley says 

 of the crayfish, he i has nothing to say to himself or any one 

 else.' He does not reflect; he makes no generalizations. All 

 his thinking is in the present and in concrete terms. He has 

 no voluntary attention, no volition in the true sense, no self- 

 control." 



