258 



Seeing seems to be the sense which fishes are pos- 

 sessed of in the greatest degree. And yet even this is 

 obscure, if we compare it to that of other animals* 

 The eye, in almost all fish, is covered with the same 

 transparent skin that covers the rest of the head, and 

 which probably serves to defend it from the water, as 

 they are without eye lids. The globe of the eye is 

 depressed before, and is furnished behind with a 

 muscle which serves to strengthen or flatten it, ac- 

 cording to the necessities of the animal. The crystal- 

 line humour, which in beasts is flat, and of the shape 

 of a button mould, in fishes is as round as a pea, or 

 sometimes oblong like an egg. 



From all this, it appears that fishes ;are extremely 

 rirar-sighted, and that even in the water they can sets 

 objects only -at a very small distance. 



Thus nature seems (o hare fitted these animals with 

 appetites and powers of an inferior kind, and formed 

 them for a sort of -passive existence in the obscure 

 and heavy element to which they are consigned : to 

 preserve their own existence, and to continue it to 

 their posterity, fill up the whole circle of .their pur. 

 suits and enjoyments. 



5, Some fishes have lungs, but in the greater part 

 the place of them is supplied by gills. As we take in 

 and throw out the air by our Jungs, so they take in 

 the air, mixed with the water, by their mouth, and 

 throw it out by their gills. 



There is always much air enclosed in water. This 

 the gills separate from it, and present to the blood, 

 as it is presented in the lungs of other animals. Each 

 gill contains a great number of bony laminae, consist* 

 ing of an infinity of bony fibres, that sustain the in- 

 numerable ramifications of the veins and arteries, 

 which present the blood extremely sub- divided, and 

 as it were, each globule by itself to the water : between 

 the lamina^, through the whole contexture of the 



