The duration of life in the elephant has been from the remotest times a matter of uncertainty and speculation. Aristotle says it was reputed to live from two to three hundred years[1], and modern zoologists have assigned to it an age very little less; CUVIER[2] allots two hundred and DE BLAINVILLE one hundred and twenty. The only attempt which I know of to establish a period historically or physiologically is that of FLEURENS, who has advanced an ingenious theory on the subject in his treatise "_De la Longévité Humaine_." He assumes the sum total of life in all animals to be equivalent to five times the number of years requisite to perfect their growth and development;--and he adopts as evidence of the period at which growth ceases, the final consolidation of the bones with their _epiphyses_; which in the young consist of cartilages; but in the adult become uniformly osseous and solid. So long as the epiphyses are distinct from the bones, the growth of the animal is proceeding, but it ceases so soon as the consolidation is complete. In man, according to FLEURENS, this consummation takes place at 20 years of age, in the horse at 5, in the dog at 2; so that conformably to this theory the respective normal age for each would be 100 years for man, 25 for the horse, and 10 for a dog. As a datum for his conclusion, FLEURENS cites the instance of one young elephant in which, at 26 years old, the epiphyses were still distinct, whereas in another, which died at 31, they were firm and adherent. Hence he draws the inference that the period of completed solidification is thirty years, and consequently that the normal age of the elephant is _one hundred and fifty_.[3] [Footnote 1: ARISTOTELES _de Anim. l. viii._ c. 9.] [Footnote 2: _Menag. de Mus. Nat._ p. 107.] [Footnote 3: FLEURENS, _De la Longévité Humaine_, pp. 82, 89.]