264 THE HARMONIES OF NATURE. 



As fishes breathe by the medium of water, and thus profit only 

 by the small quantity of oxygen contained in the air it has 

 absorbed, we cannot wonder that the circulation of their blood 

 is extremely slow. Their heart, in comparison with ours, is 

 in fact but half a one, as it merely serves to force the venous 

 blood into the gills, whence the aerated blood does not flow back 

 to the heart as with us, to be rapidly and strongly propelled 

 through the body, but proceeds immediately to the arteries, 

 which are merely aided by the contraction of the surrounding 

 muscular fibres. As respiration is a species of combustion, it is 

 evident that only a cold blood could be formed under such cir- 

 cumstances, and, as may be expected, the blunt sensations of the 

 fishes harmonize with the torpid nature of the fluid from which 

 their organs derive their sustenance. Fishes, in fact, of all 

 the vertebrates, give the least evidence of sensibility. Having 

 no elastic air at their disposal, they are dumb or nearly so, and 

 all the sentiments which voice awakens are unknown to them. 



Being only able to support themselves by pursuing a prey 

 which itself swims more or less rapidly, and having no means 

 of seizing it but by swallowing, a delicate perception of savours 

 would have been useless if Nature had bestowed it ; but 1 heir 

 tongue, almost motionless, often entirely bony, and only furnished 

 with a few slender nerves, shows us that this organ is as obtuse 

 as its little use would lead us to imagine it to be. 



Their sense of smell is equally imperfect, and their touch 

 almost annihilated at the surface of their body by the scales 

 which clothe them, and in their limbs by the want of flexibility 

 in their rays is confined to the ends of their lips, and even 

 these in some are osseous and insensible. Their ear, which is 

 entirely enclosed in the cranium, can hardly suffice to distin- 

 guish the most striking sounds. Their eyes finally are motion- 

 less as it were, and void of all that fire and animation which 

 gives so much expression to the physiognomy of the higher 

 animals ; but the structure of these organs is admirably adapted 

 to the element in which they live, by the spherical form 

 and great size and hardness of the crystalline lens, which by 

 concentrating the rays of light enables them to see with distinct- 

 ness even through so dense a medium as that which surrounds 

 them. This is, in truth, one of those wonderful provisions made 

 for the particular necessities of every living thing. 



