290 FISHES IN GENERAL. 



they avoid many of the evils produced by the atmos- 

 phere's change, and their size continues to inci 

 with their years. 



There have been two methods devised for determin- 

 ing the age of fishes; the one is by the number of 

 circles on the scales ; and the other, by the transverse 

 section of the back. When the scale of a fish is ex- 

 amined through a microscope, it will be found to con- 

 sist of a number of circles one within another, re- 

 sembling those which appear on the transverse section 

 of a tree, and offering the same information to the 

 mind; for as the circles on the tree correspond with 

 the years of its growth, so those upon the scales of the 

 fish are proportioned to its life; and by this method 

 Mr. Imffon assures us he discovered a carp to be an 

 hundred years of age. 



The age of those fish which are destitute of scales, 

 may be discovered by separating the joints of the back, 

 and then observing the number of rings which are ex- 

 hibited upon the surface where they were joined. 

 Though the discovery of these marks may be more in~ 

 gcuioiis than certain, thcr,e is no reason to doubt that 

 the generality of the species are very long-lived. Those 

 that have ponds are enabled to form an opinion of their 

 ages by making observations upon their different size. 

 .All sorts (a few of the larger ones excepted) multiply 

 their kind by hundreds' and thousands at a time ; some 

 or' the number bring forth their young alive; but the 

 greater proportion are produced from eggs, which are 

 cither deposited at the bottom or the edges of the wa- 

 ters, or float in millions on the surface of the stream. 

 Of these eggs scarce one in an hundred produces an 

 animal, as the aquatic birds devour those that are found 

 on the edges of the water, and those at the bottom be- 



