88 FISHES AND FISHING. 



Having thus concisely, and I trust clearly, ex- 

 plained the anatomy and physiology of the sense of 

 hearing in man, and an epitome of that of fishes, 

 it will be obvious that as vibration of the mem- 

 brana tympani in the former, carried on by the 

 ossicula to the auditory nerves, and thence to the 

 brain, produces the sense we denominate hearing ; so, 

 if the ossicula in fish are caused to vibrate, a similar 

 communication will be made to the brain of fishes. 

 The question to be now solved is, how that vibration 

 is effected ; and to elucidate this, we must investigate 

 the nature of the two different elements in which 

 terrestrial animals and fish exist. John Hunter, in 

 his " Economy of Animals," says, that before the time 

 of Geoffroi the different mediums in which land and 

 water animals existed were not considered : this is 

 much about as correct as that Geoffroi was the first 

 to assert that fish had the sense of hearing. Why, 

 the commencement of the first book of Oppian shews 

 how erroneous and unfounded these assertions are. 



Air which supports and nourishes terrestrial ani- 

 mals is fatal to fish, (some species sooner than others,) 

 if they remain out of the water during a short time ; 

 and yet, like man, and other animals of that class, 

 they cannot live unless they imbibe oxygen ; only 

 there is this difference, man inhales it from the at- 

 mosphere, whilst fish extract oxygen from the water 



