238 A HISTORY OF 



There have been two methods devised for determining the age of 

 iishes, which are more ingenious than certain ; the one is by the cir 

 cles of the scales, the other by the transverse section of the back-bone 

 The first method is this. When a fish's scale is examined through a 

 microscope, it will be found to consist of a number of circles, one cir- 

 cle within another, in some measure resembling those which appear 

 upon the transverse section of a tree, and supposed to offer the same 

 information. For as in trees we can tell their age by the number 01 

 their circles, so in fishes we can tell them by the number of their cir 

 cles in every scale, reckoning one ring for every year of the animal'? 

 existence. By this method, Mr. Buffon found a carp, whose scales he 

 examined, to be not less than a hundred years old ; a thing almost in- 

 credible, had we not several accounts in other authors which tend to 

 confirm the discovery. Gesner brings us an instance of one of the 

 same age ; and Albertus of one more than double that period. 



The age of the skate and the ray, that want scales, may be known 

 by the other method, which is, by separating the joints of the back- 

 bone, and then minutely observing the number of rings which the 

 surface where it was joined exhibits. By this the fish's age is said 

 to- be known ; and perhaps with as much certainty as in the former 

 instance. 



But how unsatisfactory soever these marks may be, we have no 

 reason to doubt the great ages of some fishes. Those that have 

 ponds, often know the oldest by their superior size. But the longevity 

 of these animals is nothing when compared to their fecundity. All 

 sorts, a few of the larger ones excepted, multiply their kind, some by 

 hundreds, and some by millions. There are some that bring forth 

 their young alive, and some that only produce eggs; the former are 

 rather the least fruitful : yet even these are seen to produce in great 

 abundance. The viviparous blenny, for instance, brings forth two or 

 three hundred at a time, all alive and playing round the parent toge- 

 ther. Those who exclude their progeny in a more imperfect state, 

 and produce eggs, which they are obliged to leave to chance, either 

 on the bottom, at the edge of the water, or floating on the surface 

 where it is deeper, are all much more prolific, and seem to proportion 

 their stock to the danger there is of its consumption. Of these eggs, 

 thus deposited, scarce one in a hundred brings forth an animal ; they 

 are devoured by all the lesser fry that frequent the shores, by aquatic 

 birds near the margin, and by the larger fish in deep water. Still, 

 however, there are enough for supplying the deep with inhabitants ; 

 and, notwithstanding their own rapacity, and that of fowls of various 

 tribes, the numbers that escape are sufficient to relieve the wants of a 

 very considerable part of mankind. Indeed, when we consider the 

 numbers that a single fish is capable of producing, the amount will 

 seem astonishing. If, for instance, we should be told of a being so 

 yery prolific, that in a single season it could bring forth as many of 

 ts kind as there are inhabitants in England, it would strike us with 

 sarprise ; yet a single cod produces full that number. The cod 

 spawns in one season, as Lewenhoeck assures us, above nine millions 

 of eggs or peas contained in one single roe. The flounder is com 

 monly known to produce above one million and the mackarel above 

 five hundred thousand. Such an amazing increase, if permitted to 



