of them nature has given to some species a pal- 

 mated process connected with the iris, which the 

 animal has the power of raising or depressing 

 according to circumstances. The humours of 

 the eye are proportionally in greater quantities, 

 or much larger than those of animals living in 

 air. Thus the eye of the cod is very nearly of 

 the same weight, and its axis of the same length 

 as the eye of the ox. The cornea, however, is 

 not so convex as that of land animals, because 

 little or no refraction of light takes place in this 

 membrane in fishes; but then the crystalline lens, 

 on the contrary, is almost spherical, compensat-. 

 ing thus for the comparative flatness of the cor- 

 nea. In all animals the eye is a perfect optical 

 instrument, and admirably adapted to the cir- 

 cumstances in which each species is placed. We 

 know it to be composed of membranes and hu- 

 mours of different densities, so that they may 

 transmit and refract the rays of light with the 

 greatest regularity and exactness. In the eyes 

 of all animated beings, we see the wisdom and 

 beneficence of the Creator. If the animal dwell 

 in the water, the cornea is flat, and the lens 

 spherical ; if on the surface of the earth, we find, 

 on the contrary, the cornea more projecting, and 

 the lens more flat ; and again, if it wing its airy 

 flight above us, its cornea is the most projecting, 

 and its lens the flattest of all. 



That fishes hear also although the fact was 

 for a long time doubted is sufficiently obvious 

 from many circumstances, and among the rest, 



