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SUPPLEMENT ON 



phenomena. The first is produced by those organs which 

 endow the beings that possess them with two faculties ; 

 namely, that of growing, or being developed by the incorpo- 

 ration of foreign substances, which, for a time, participate in 

 the vital action ; and that of reproducing or engendering 

 individuals similar to themselves. The second series consists 

 in the means accorded to living beings of changing place at 

 will, either Avholly or in part, and those by which they can 

 perceive or feel the action which other bodies, by their quali- 

 ties, can exercise upon them. These are the four grand 

 functions of nutrition, generation, locomotion, and sensa- 

 tion. 



Nutrition and generation take place in certain organized 

 beings, independently of the other two functions. This is a 

 more simple mode of existence, but the beings who so exist, 

 possessing fewer faculties, must of necessity remain, and be 

 developed in the same place where their germs were depo- 

 sited. 



The faculties of motion and sensation never exist in the 

 same isolated way in any living beings, because they must be 

 nourished and reproduced. Bodies thus organized, are more 

 complicated, for they unite the two kinds of life. It is by 

 the organs which give rise to the faculties of motion and sen- 

 sation, and perform those functions in such a variety of 

 modes, that animals are distinguished from vegetables, which 

 cannot change place, and which, as far as we can discover, 

 have no vestige of sensation. 



It may be further observed, that these organs of motion 

 and sensation, have modified the other two functions. An 

 animal with the power of changing place altogether, or in 

 part, and by its own proper motion, must, if the medium 

 which it inhabits be not liquid, or if other beings do not 

 provide it with nourishment, proceed in search of its food, 

 introduce it into an interior cavity, so organized as to distri- 



