HISTORY OF FISH. 157 



effort : fhoals of one fpecies follow thofe of another 

 through vaft tracks of ocean, from the vicinity of 

 the pole even down to the equator. Thus the cod, 

 from the banks of Newfoundland, purfues the whit- 

 ing, which flies before it even to the fouthern 

 fhores of Spain. The cachalot, a fpecies of whale, 

 is faid, in the fame manner, to purfue a Ihoal of 

 herrings, and to fwallow hundreds in a mouthful. 



This may be one caufe of the annual migration 

 of fifties from one part of the ocean to the other ; 

 but there are different motives, which come in aid 

 of this alfo. Fifties may be induced to change the 

 place of their refidence, for one more fuited to 

 their conilitutions, or more adapted to depofiting 

 their fpawn. 



All forts of fifti, a few of the larger ones excepted, 

 multiply their kind, fome by hundreds and fome by 

 millions. There are fome that bring forth their 

 young alive, and fome that only produce eggs : the 

 former are rather the leaft fruitful : yet even thele 

 are feen to produce in great abundance. The vi- 

 viparous blenny, for inflance, brings forth 2 or 300 

 at a time, all alive and playing round the parent 

 together. Thofe who exclude their progeny in a 

 more imperfect ftate, and produce eggs, which they 

 are obliged to leave to chance, either on the bottom 

 at the edge of the fhore, or floating on the fur- 

 face of deep water, are all much more prolific; and 

 ieem to proportion their ftock to the danger there is 

 of its confumption. Of thefe eggs thus dcpofited, 

 fcarce one in an hundred brings forth an animal : 

 they are devoured by all the lefifer fry that frequent 

 the fhores ; by aquatic birds near the margin, and 

 by the larger fifh in deep water. Still, however, 

 there are enough for fupplying the deep with inha- 

 bitants : and, notwithstanding their own rapacity, 

 and that of the fowls of various tribes, the numbers 

 that efcape are fufficient to relieve the wants of a 

 very coniiderablc part of mankind. Indeed, whr 



conlider 



