56(» HISIORV OF 



it is most probable tliut tbese minute alterations often take 

 place. 



As a proof of this, during the month of July, there appeal 

 near Greenwich, innumerable shoals of small lishes, which art 

 known to the Londoners by the name of White bait. It is uni- 

 versally 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 ma- 

 turity. The quantity is amazing; and the fish that produces 

 them in such numbei-s must be in plenty, though it is not yet 

 known what that fish is, as they correspond with no other spe- 

 cies whatever. They most resemble the smelt in form ; and yet 

 they want a fin which that animal is never without. They can- 

 not be the bleak, as they are never found in other rivers where 

 the bleak breed in great abundance. It is most probable, there- 

 fore, 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 propor- 

 tion 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 in- 

 fluence of vital warmth it requires to reach through all its reces- 

 ses, and to unfold the dormant springs that wait to be put into 

 motion. 



The maimer 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 con- 

 trary, when the time of coupling is over, their appetite returns ; 

 they re-assume their natural agility, and their scales become 

 brilliant and beautiful. 



-Although the usual way with sjiinous 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 hiis 



