FISHES IN GENERAL. 233 



a muscle, which serves to lengthen or flatten it according to the ne- 

 cessities of the animal. The crystaline humour, which in quadrupeds 

 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 

 fish are extremely near-sighted ; and that, even in the water, they can 

 see objects at a very small distance. This distance might very easily 

 be ascertained by comparing the refraction of bodies in the water, 

 with that formed by a lens that is spherical. Those unskilled in ma- 

 thematical calculations, will have a general idea of this, from the 

 glasses used by near-sighted people. Those whose crystaline humour 

 is too convex, or, in other words, too round, are always very near- 

 sighted, and obliged to use concave glasses, to correct the imperfec- 

 tions of Nature. The crystaline humour of fish is so round, that it is 

 not in the power of any glasses, much less of water, to correct their 

 vision. This crystaline humour in fishes, all must have seen, being 

 that little hard pea-like substance which is found in their eyes after 

 boiling. In the natural state it is transparent, and not much harder 

 than a jelly. 



From all this, it appears how far fish fall behind terrestrial animals 

 in their sensations, and consequently, in their enjoyments. Even their 

 brain, which is by some supposed to be of a size with every animal's 

 understanding, shows that fish are inferior even to birds in this 

 particular. It is divided into three parts, surrounded with a whitish 

 froth, and gives off nerves, as well to the senses of sight as of smell- 

 ing. In some fish it is gray, in others white ; in some it is flatted, in 

 others round ; but in aH extremely small, compared to the bulk of the 

 animal. 



Thus Nature seems to have fitted these animals with appetites and 

 powers of an inferior kind, and formed them for a sort of passive ex- 

 istence in the obscure and heavy element to which they are consign- 

 ed. To preserve their own existence, and to continue it to their 

 posterity, fill up the whole circle of their pursuits and enjoyments ; 

 to these they are impelled rather by necessity than choice, and seem 

 mechanically excited to every fruition. Their senses are incapable 

 of making any distinctions ; but they drive forward in pursuit of 

 whatever they can swallow, conquer, or enjoy. 



A ceaseless desire of food seems to give the ruling impulse to all 

 their motions. This appetite impels them to encounter every dan- 

 ger ; and indeed their rapacity seems insatiable. Even when taken 

 out of the water, and almost expiring, they greedily swallow the very 

 bait by which they were allured to destruction. 



The maw is, in general, placed next the moutn, And hough pos- 

 sessed of no sensible heat, is, however, endued with a surprising fa- 

 culty of digestion. Its digestive power seems, in some measure, to 

 increase with the quantity of food it is supplied with ; a single pike 

 having been known to devour a hundred roaches in three days. Its 

 faculties also are as extraordinary ; for it digests not only fish, but 

 much harder substances; prawns, crabs, and lobsters, shells and all. 

 These the cod or the sturgeon will not only devour, but dissolve 

 down, though their shells are so much harder than the sides of the 

 stomach which contains them. This amazing faculty in the cold 

 maw of fishes, has justly excited the curiosity of philosophy rs, and 



