264 THE SENSORIAL FUNCTIONS. 



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 im- 

 portant that the animal, of whose sensitive faculties we are 

 examining the successive endowment, should be apprized. 

 It is more especially necessary that he should acquire an 

 accurate 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 sup- 

 ply his wants, or procure him gratification; and which also 

 apprize him of danger while it is yet remote, and may be 

 avoided. Endowed with the power of combining all these 

 perceptions, he commences his career of sensitive and intel- 

 lectual existence; and though he soon learns that he is de- 

 pendent 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 control over 

 many of those changes, and that he moves his limbs by his 

 own voluntary act; movements which originally, and of 

 themselves, appear, in most animals, to be productive of 

 great enjoyment. 



To a person unused to reflection, the phenomena of sen- 

 sation and perception may appear to require no elaborate 

 investigation. That he may behold external objects, nothing 

 more seems necessary than directing his eyes towards them. 

 He feels as if the sight of those objects were a necessary 

 consequence of the motion of his eye-balls, and he dreams 

 not that there can be any thing marvellous in the function 

 of the eye, or that any other organ is concerned in this sim- 

 ple act of vision. If he wishes to ascertain the solidity of 

 an object within his reach, he knows that he has but to 

 stretch forth his hand, and to feel in what degree it resists 

 the pressure he gives to it. No exertion even of this kind 

 is required for hearing the voices of his companions, or be- 



