THE VISION OF A TROUT. 79 



vibratory motion. Sound is communicated by the vibration 

 of the air or other elements but similar vibrations of 

 these elements can be produced without sound and the 

 trout may, therefore, depend on the tactile nerves rather 

 than on the auditory ones. If trout were capable of 

 hearing, I do not think that wading would be so productive 

 of good results as it undoubtedly is. The noise of one's 

 brogues on the pebbles can be distinguished for considerably 

 over half a mile in perfectly quiet water in rivers, and for 

 miles in lakes. 



THE VISION OF A TROUT. 



Although it is supposed that trout cannot see an 

 object which is situated directly behind them, that is, in 

 the direction of their tails, so far as I am aware, the 

 angle at which their sight is limited behind each shoulder 

 has never been discussed. 



It can be assumed that this limit of sight is a variable 

 one, depending on the physiological characteristics of each 

 individual fish, and also varying at different periods accord- 

 ing to the seasonal changes, and the age and condition of 

 the fish. 



From my own observation of trout I consider that, if 

 the eyes of a trout are assumed as being the centre of 

 the horizontal plane in which it is lying, it can see in 

 that place from a point right ahead to an angle of about 



