318 



HISTORY OF FISHES. 



at present distributes health and plenty to the 

 shore, would but load it with putrefaction. 



In the propagation of all fish, some degree 

 of warmth seems absolutely necessary, not 

 only to their preservation, but to the advance- 

 ment of their posterity. Their spawn is al- 

 ways deposited in those places where the sun 

 beams may reach them, either at the bottom 

 of shallow shores, or floating on the surface in 

 deeper waters. A small degree of heat answers 

 all the purposes of incubation, and the animal 

 issues from the egg in its state of perfect for- 

 mation, never to undergo any succeeding 

 change. 



Yet, still I have some doubts whether most 

 fish come from the egg completely formed. 

 We know that in all the frog tribe, and many 

 of the lizard kind, they are produced from the 

 egg in an imperfect form. The tadpole, or 

 young frog, with its enormous head and slen- 

 der tail, are well known; a species of the lizard 

 also, which is excluded from the shell without 

 legs, only acquires them by degrees, and not 

 till after some time does it put off ifs serpent 

 form. It is probable that some kinds of fish 

 in like manner suffer a change ; and though 

 it be too inconsiderable to strike the fisherman 

 or the inattentive spectator, yet it makes a 

 very material difference to the naturalist, and 

 would, perhaps, disarrange his most favourite 

 systems. A slight alteration in the fins or 

 bones that cover the gills would overturn the 

 whole fabric of the most applauded ichthyolo- 

 gist; and yet, as I observed, it is most proba- 

 ble that these minute alterations often take 

 place. 



As a proof of this, during the month of 

 July, there appear near Greenwich, innumer- 

 able shoals of small fishes, which are known 

 to the Londoners by the name of White bait. 

 It is universally agreed that they are the 

 young of some fish ; they are never seen but 

 at this time of the year, and never found to 

 have any roe, a circumstance that proves their 

 not being come to maturity. The quantity is 

 amazrhg ; and the fish that produces them in 

 such numbers must be in plenty, though it is 

 not yet known what that fish is, as they cor- 

 respond with no other species whatever. They 

 most resemble the smelt in form ; and yet they 

 want a fin, which that animal is never without 

 They cannot be the bleak, as they are never 

 found in other rivers where the bleak breed 

 in great abundance. It is most probable, 

 therefore, that they are the young of some 

 animal not yet come to their perfect form, and 

 therefore reducible to no present system. 



The time that spinous fishes continue in the 

 pea is in proportion to the size of the kind. It 

 is a rule that chiefly holds through nature, 

 that the larger the animals are, the longer 

 they continue before exclusion. This I say 



holds generally through all nature, though it 

 is not easy to assign a cause for so well known 

 a truth. It may probably be, that as all large 

 bodies take a longer time to grow hot than 

 small ones, so the larger the egg, the longer 

 influence of vital warmth it requires to reach 

 through all its recesses, and to unfold the 

 dormant springs that wait to be put into 

 motion. 



The maimei in which the eggs of fishes are 

 impregnated is wholly unknown. All that 

 obviously offers is, that in ponds the sexes are 

 often seen together among the long grass at 

 the edge of the water; that there they seem to 

 struggle; and that during this time they are 

 in a state of suffering; they grow thin ; they 

 lose their appetite, and their flesh becomes 

 flabby; the scales of some grow rough, and 

 they lose their lustre. On the contrary, when 

 the time of coupling is over, their appetite 

 returns ; they re-assume their natural agility, 

 and their scales become brilliant and beau- 

 tiful. 



Although the usual way with spinous fishes 

 is to produce by spawn ; yet there are some, 

 such as the eel and the blenny, that are known 

 to bring forth their young alive. Bowlker, 

 who has written a treatise upon fishing, seems 

 to determine the question relative lo the vivi. 

 parous production of eels, upon the authority 

 of one or two credible witnesses. An eel, 

 opened' in the presence of several persons of 

 credit, was found to have an infinite number 

 of little creatures, closely wrapped up together 

 in a lump, about the size of a nutmeg, which 

 being put into a basin of water, soon separated, 

 and swam about: yet still, whether these may 

 not have been worms generated in the animal's 

 body, remains a doubt ; for there are scarcely 

 any fishes that are not infested with worms in 

 that manner. 1 



With respect to the growth of fishes, it is 

 observed, that among carps, particularly the 

 first year, they grew to about the size of the 

 leaf of a willow-tree ; at two years, they are 

 about four inches long. They grow but one 

 inch more the third season, which is five inches. 

 Those of four years old are about six inches; 

 and seven after the fifth. From that to eight 

 years old they are found to be large in pro- 

 portion to the goodness of the pond, from eight 

 to twelve inches. With regard to sea-fish, 

 the fishermen assure us, that a fish must be 

 six years old before it is fit to be served up to 

 table. They instance it in the growth of a 

 mackarel. They assure us that those of a 

 year old are as large as one's finger ; that those 

 of two years, are about twice tliat length ; at 

 three and four years, they are that small kind 

 of mackarel that have neither milts nor roes ; 



1 The eel, it is known, is viviparous. 



