EVOLUTION OF LIFE. 61 



sensitive nerves, of sensation. This sentient 

 power seems inherent in the nerves which the 

 organs of sense contain, and these nerves are 

 the seat in which the proximate cause of sensa- 

 tion actually abides. The cause of sensation, 

 does not abide in the external substance, 

 but in the organ by which the impression is 

 received. It is owing to this sensitive power, 

 that we behold animals display fondness and 

 aversion, action and remission, appetite and 

 inanition; it is by the energy of these or- 

 gans, that animals are able to distinguish, 

 without experience, in an intuitive manner, 

 not only the fitness of the medium in which, 

 by nature, they are destined to reside, but the 

 substances also, which are best fitted for the 

 support and nourishment of their frame. It 

 is owing to this sensitive power, that the dnck 

 and the chick in ovo, after having pecked open 

 the shell in which they were enclosed, take dif- 

 ferent directions ; the one waddles into the 

 water, the other hops into the barn ; that the 

 infant, as soon as it is born, expresses by the 

 motion of its tongue and lips, its wants and its 

 appetites, and selects milk, and rejects vine- 

 gar ; that we behold in the leech, its fondness 

 for blood, and aversion to salt. 



It is owing to the perfection of this sensitive 

 power, which these organs of sense contain, 

 that their energy is strong, and that the gratiti- 



