257 



more fiat. It was formerly believed they did not hoar 

 at all; but from later experiments, there is reason to 

 believe that several species of them do hear, though 

 but in a low degree. Over the two holes in their 

 head, which serve for smelling, a fine membrane is 

 spread, by which means they can open and shut them 

 at pleasure; a contrivance highly necessary for crea- 

 tures that live in the water. 



The sense of smelling which in beasts is so exquisite, 

 and among birds is not wholly unknown, seems given 

 to fishes iu a very moderate proportion. It is true 

 that all tishes have one or more nostrils, and even those 

 that have not the holes perceptible without, yet have 

 the proper formation of the bones for smelling within. 

 But as air is the only medium we know, for the distri- 

 bution of odours, it cannot be supposed that these 

 animals residing in water can be possessed of any 

 power of being affected by them, if they have any 

 perception of smells, it must be in the sa;ne manner as 

 we distinguish by our taste ; and it is probable, the ol- 

 factory membrane in fishes, serve them instead of a 

 distinguishing palate : by this they judge of substances 

 that first tincturing the water with their vapours, are 

 thus sent to the nostrils of the fish, and no doubt pro- 

 duce some kind of sensation. This most probably 

 must be the use of that organ in those animals, as 

 otherwise there would be the instrument of a sense 

 provided for them, without any power in them of en- 

 joyment. 



Hearing in fishes is found still more imperfect, if it 

 be found at all. Certain it is, that anatomists have 

 not been able to discover, except in the whale kind, 

 the smallest traces of an organ of hearing, either with- 

 in or without the head. Indeed, of what advantage 

 would this sense be to animals that are incapable of 

 making themselves heard ? They have no voice to com. 

 mnnicate with each other, and consequently have no 

 need of an organ for hearing. 



