How to obtain it. 271 



ringing of a bell, we have heard of fish being summoned to a meal 

 by the performance, and I have often heard this story brought up 

 as a direct proof of fish being able to hear. I once had a visitor 

 who was so sure that the fish, when trained to do so, would obey 

 the summons, that I at length told him that I had some ponds 

 full of fish that would do the same, but when I explained that it 

 made not the slightest difference to them whether the tongue of 

 the bell happened to be in or out, even he began to v be less 

 credulous. Having procured a bell, and removed the tongue, I 

 went out for his satisfaction and pretended to ring it, when the 

 fish came at once. 



Although no notice is taken of sounds made in the air, yet 

 we find that trout are keenly sensible to vibrations of the water, 

 which are probably transmitted to the body of the fish, and there 

 is little doubt that noises made in the water are heard by the 

 trout in this way. Dr. Francis Day, in his British and Irish 

 Salmonidcz (p. 19), says: "Hearing is developed in fishes, and 

 it is very remarkable how any diversity of opinion can exist as to 

 their possessing this sense." A little further on he says : " But 

 the chief mode in which hearing is carried on must be due to* the 

 surface of the fish being -affected by vibrations of the water, and 

 the sounds are transmitted directly to the internal ear, or else by 

 means of the air bladder acting as a sounding board." Here we 

 must leave this interesting question. Its bearing on the cultivation 

 of trout is rather an important one, as cases may often arise in 

 which the fish might be so disturbed by noises as to be injuriously 

 affected thereby. But it is not so, for as regards noises made in 

 the air the fish are neither alarmed when feeding, nor yet driven 

 off their spawning beds, provided always that they see nothing. 



Some scientists have supposed the lateral line to have some 

 connection with the hearing powers of fish, hence it has been 

 called " the lateral sensory apparatus." It consists of a series 

 of punctures forming tubes from which nerves run, and com- 

 municate with the head and possibly with the organs of hearing. 

 These tubes also discharge a mucous secretion. 



Do fishes sleep ? is a question I am sometimes asked. That 

 they do there can be little doubt, but whether sleep is to them 

 exactly what it is to the mammalia is another thing. Trout cannot 



