OF NATURAL HISTORY. 509 



The general caufes of death have already been mentioned. But, 

 in women, the operation of thefe caufes is frequently retarded. In 

 the female fex, the bones, the cartilages, the mufcles, as well as every 

 other part of the body, are fofter and lefs folid than thofe of men : 

 Neither are they generally fo much fubjedted to bodily exertions. 

 Their conftltuent parts, accordingly, require more time in "hardening 

 to that degree which occafions death. Women, of courfe, ought to 

 live longer than men. This reafoning is confirmed by the bills of 

 mortality ; for, upon confulting them, it appears, that, after women 

 have pafled a certain time, they live much longer than men who 

 have reached the fame period. The duration of the lives of animals 

 may, in fome meafure, be eftimated by the time occupied in their 

 growth. An animal, or even a plant, as we learn from experience, 

 which acquires maturity in a fhort time, periflies much fooner than 

 thofe which are longer in arriving at that period. In the human 

 fpecies, when individuals grow with uncommon rapidity, they ge- 

 nerally die young. This circumftance feems to have given rife to 

 the common proverbial expreffion, Soon rtpefoon rotten, Man grows 

 in ftature till he be fixteen or eighteen years of age ; but the thick- 

 nefs of his body is not completely unfolded before that of thirty. 

 Dogs acquire their full length in one year ; but their growth in 

 thicknefs is not finifhed till the end of the fecond. A man, who 

 continues to grow for thirty years, may live ninety or a hundred : 

 But a dog, whofe growth terminates in two or three years, lives on- 

 ly ten or twelve. The fame obfervation is applicable to moft ani- 

 mals. Fifhes continue to grow for a great number of years. Some 

 of them, accordingly, live during feveral centuries ; becaufe their 

 bones and cartilages feldom acquire the denfity of thofe of other 

 animals. It may, therefore, be confidered as a general faft, that 

 large animals live longer than fmall ones, becaufe the former require 

 more time to complete their growth. Thus the caufes of our diffo- 

 lutioxi are inevitable ; and it is equally impoffible to retard that fatal 



period, 



