6 3 o THE SENSES. 



the retina seems external to the body : the ringing of the 

 ears in disease is felt as if the sound came from some 

 distance : the mind referring it to the outer world from 

 which it is in the habit of receiving the like impression. 



Moreover, the mind not only perceives the sensations, 

 and interprets them according to ideas previously obtained, 

 but it has a direct influence upon them, imparting to them 

 intensity by its faculty of attention. Without simultaneous 

 attention, all sensations are only obscurely, if at all, per- 

 ceived. If the mind be torpid in indolence, or if the 

 attention be withdrawn from the nerves of sense in intel- 

 lectual contemplation, deep speculations, or an intense 

 passion, the sensations of the nerves make no impression 

 upon the mind ; they are not perceived, that is to say, 

 they are not communicated to the conscious " self," or with 

 so little intensity, that the mind is unable to retain the 

 impression, or only recollects it some time after, when it is 

 freed from the preponderating influence of the idea which 

 had occupied it. 



This power of attention to the sensations derived from a 

 single organ, may also be exercised in a single portion of 

 a sentient organ, and thus enable one to discern the detail 

 of what would otherwise be a single sensation. For 

 example, by well-directed attention, one can distinguish 

 each of the many tones simultaneously emitted by an 

 orchestra, and can even follow the weaker tones of one 

 instrument apart from the other sounds, of which the im- 

 pressions being not attended to are less vividly perceived. 

 So, also, if one endeavours to direct attention to the whole 

 field of vision at the same time, nothing is seen distinctly ; 

 but when the attention is directed first to this, then to that 

 part, and analyses the detail of the sensation, the part to 

 which the mind is directed is perceived with more distinct- 

 ness than the rest of the same sensation. 



