34 OF FISHES IN GENERAL. 



allow four or five times that fpace for the period of its 

 life, it will not exceed thirty years. 



Different methods have been devifed for afcertaining 

 the age of fiflies, fome of which will, perhaps, pretty 

 accurately determine this matter. The ingenious Mr. 

 Hiddo/iroam, a Swede, has attempted to compute their 

 ages by the number of concentric circles obferved in a 

 tranfverfe fe£lion of the vertebrae of the back ; and it has 

 been found, that each circle, like that in the fedlion of 

 a tree, correfponds to a year of the animal's life. In 

 confirmation of this fa£l, experiments have been made on 

 different individuals of various fiz.es, but of the fame age, 

 whofe concentric circles have always been of an equal 

 number ; whereas a young fifla differs from an older one 

 of the fame fpecies, by having a fmaller number of thefe 

 circles. Ey this method of computation, feveral fiflx 

 were found from fifteen to twenty years, but none gave 

 indications of a greater age. 



Another method of computing the age of filhes, prac- 

 tifed by M. de BuffoJt, is by numbering the concentric 

 circles upon their fcales * ; but as this requires a more 

 minute examination, it is, of confequence, liable to 

 greater uncertainty. On examining the fc^ie of a fifli 

 through a microfcope, it exhibits a number of circles, 

 one within another, refembling thofe in the vertebiae of 

 the back, and, like them, every circle reprefents a year 

 of the fiili's life. A fcale of a carp, thus examined, an- 

 nounced the animal to be no kfs than an hundred years; 

 a longevity lefs incredible, becaufe confirmed by the tef- 

 tirr.ony of feveral different authors f, fome of whom have 

 aflerted, that this fifh lives twice that period. 



The 



* Fide Kifl. gcner. ct part. f Gelxicr and Albcrtus, 



