260 UPLAND AND MEADOW. 



berers, at least, at times? But do fishes sleep like other 

 animals ? He who wanders along a slnggish creek or 

 any still water, in pursuit of them, knows full well how 

 seldom they are caught napping; and it is a difficult 

 matter to say when a fish is asleep. Certainly, they do 

 not give just such evidence of it as do mammals or 

 birds; and while in a physiological sense it is true, the 

 statement, as it stands, is somewhat misleading. 



Fish that habitually or occasionally rest upon the bot- 

 tom of the stream might readily go to sleep, and no 

 one suspect their condition ; but this is not true of fishes 

 that never rest in this way. How do they sleep ? Take 

 so restless a species as the little silver-finned minnow. 

 It must sleep, it seems ; but how ? Do the fins that pre- 

 serve the upright position of the fish move involunta- 

 rily, just as we breathe without being conscious of the 

 effort ? If so, then such sleeping fish would be drifted by 

 the current and be hopelessly exposed to many dangers. 

 This, therefore, cannot be true ; and yet these fish can- 

 not go into quiet waters, for here they perish in a short 

 time. If, on the other hand, their entire muscular ac- 

 tivity is kept at its maximum, and they can still sleep, 

 then it is slumbering in a manner quite unlike that of 

 other animals. 



Of such fishes as I have observed, while they were 

 confined in aquaria, there did seem to be a listless con- 

 dition at times, coupled with a lack-lustre expression of 

 the eyes, which suggested sleep. This was the more 

 noticeable when I aroused them, for the eye suddenly 

 lighted up, and was very different in its general appear- 

 ance from what it had been. 



