OF NATURAL HISTORY. 505 



but thefe exceptions are confirmations of what we have advanced. 

 Mankind, in the early ages of the world, have been faid to live for 

 feveral centuries. We mean not to contradid: the aflertion. But 

 we muft remark, that, if ever men lived fo long, they muft have 

 been very different, both in the ftrudure of their bodies and in their 

 manners, from thofe who now exift. From infancy to manhood, 

 there is a gradual growth or extenfion of our organs. After this 

 period, and when we advance in years, the bones harden, the mufcles 

 turn ftiflF, the cartilages are converted into bones, the membranes in- 

 to cartilages, the ftomach and bowels lofe their tone, and the whole 

 fabric, inftead of being foft, flexible, and obedient to the inclinations, 

 or even the commands of the mind, becomes rigid, inadive, and 

 feeble. Thefe are the general and progreffive caufes of death, and 

 they are common to all animals. There are modes of living more 

 favourable to health than others. But examples are not wanting of 

 men who have arrived at extreme old age, without obferving either 

 temperance, or any of the other modes of living which are gene- 

 rally fuppofed to be favourable to longevity. Some men, who lived, 

 tejuperately, and even abftemioufly, have reached to great ages : 

 Others, who ohferved the very oppofite condud, who lived freely, 

 and often intemperately, have had their exiftence equally pro- 

 longed. But, in general, notwithftanding a few exceptions, tem- 

 perance, a placid and chearful difpofition, moderate exercif^ and. 

 proper exertions of mind, contribute, in no uncommon degree, to. 

 -the prolongation of life.. 



A few examples of longevity in the human fpecies, though no 

 general conclufions can be drawn from them, may not be incurious 

 to the reader. We fhall not go back to a remote and obfcurs anti- 

 quity, but confine ourfelves to more modern times, when the modes, 

 of living were nearly the fame as they are at prefent. 



-j- ,3s ' On: 



