SENSATION. .]/ I 



As the sphere of perception is enlarged, it is 

 made to comprehend, not merely those objects 

 which are actually in contact with the body, but 

 also those which are at a distance, and of the 

 existence and properties of which it is highly 

 important that the animal, of whose sensitive 

 faculties we are examining the successive en- 

 dowment, should be apprized. It is more espe- 

 cially necessary that he should acquire an accu- 

 rate 'knowledge of the distances, situations and 

 motions of surrounding objects. Nature has 

 accordingly provided suitable organizations for 

 vision, for hearing, and for the perception of 

 odours ; all of which senses establish extensive 

 relations between him and the external world, 

 and give him the command of various objects 

 which are necessary to supply his wants, or 

 procure him gratification ; and which also ap- 

 prize him of danger while it is yet remote^ 

 and may be avoided. Endowed with the power 

 of combining all these perceptions, he com- 

 mences his career of sensitive and intellectual 

 existence ; and though he soon learns that he 

 is dependent for most of his sensations on the 

 changes which take place in the external 

 world, he is also conscious of an internal 

 power, which gives him some kind of con^ 

 trol over many of those changes, and that he 

 moves his limbs by his own voluntary act; 



