CHAP. 5. ON VITAL FUNCTIONS. 187 



may have indulged, from time to time, in any 

 of them, they may have acquired what are 



multiplied by civilization. The effect of civilization in pro- 

 ducing variety and disease, is also observable in those animals 

 which have been domesticated. In proportion as they have 

 approached the habitations of man, and lived under his roof 

 and protection, their natural habits have become altered and 

 perverted, the size and figure of their bodies changed and 

 various ; and they have, like man, to whom they owe their 

 deformity, become the subjects of numberless diseases. I 

 have dissected many domestic animals, and have often found 

 in them extensive ossifications of soft parts, "and preternatural 

 tumours : but I never recollect to have found any marks of 

 organic disease in those which may be truly called wild. 



Human nature, from the influence of various causes, having 

 been infinitely varied, and constitutional varieties being in 

 some measure transcendant, every one is probably born with 

 some peculiarity, and, perhaps, more or less, with some par- 

 ticular tendency to disease. Peculiarities of character being 

 afterwards modified and diversified by education, the varieties 

 become almost infinite. The subject of variety leads me 

 to the following considerations. Of all the animated and 

 vegetable beings which inhabit the Earth, no two species are 

 alike, each has* its peculiarities. From the concretions of the 

 earth itself, up to man, there appears to be a succession, to 

 use common language, of more and more perfect beings. 

 From saxeous excrescences we ascend to Lichens, and, 

 through all the infinitely various tribes of vegetables, to the 

 Polypus and Star Fish, connecting, as it would seem, vegeta- 

 ble and animal life together. From these every link in the 

 chain appears filled up by numberless animals possessing 



