xii.] THE METAPHYSICS OF SENSATION. 301 



size, and thereby 1 arrive at the notion of figure. More- 

 over, if the sovereign slides over the palm, I acquire a 

 distinct conception of change of place or motion, and 

 of the direction of that motion. For as the sovereign 

 slides, it affects new nerve-endings, and gives rise to new 

 states of consciousness. Each of them is definitely and 

 separately localized by a reflex act of the mind, which, 

 at the same time, becomes aware of the difference between 

 two successive localizations; and therefore of change of 

 place, which is motion. 



If, while the sovereign lies on the hand, the latter 

 being kept quite steady, the fore-arm is gradually and 

 slowly raised ; the tactile sensations, with all their accom- 

 paniments, remain exactly as they were. But, at the 

 same time, something new is introduced; namely, the 

 sense of effort. If I try to discover where this sense of 

 effort seems to be, I find myself somewhat perplexed at 

 first ; but, if I hold the fore-arm in position long enough, 

 I become aware of an obscure sense of fatigue, which is 

 apparently seated either in the muscles of the arm, or in 

 the integument directly over them. The fatigue seems 

 to be related to the sense of effort, in much the same 

 way as the pain which supervenes upon the original 

 sense of contact, when a pin is slowly pressed against 

 the skin, is related to touch. 



A little attention will show that this sense of effort 

 accompanies every muscular contraction by which the 

 limbs, or other parts of the body, are moved. By its 

 agency the fact of their movement is known ; while the 

 direction of the motion is given by the accompanying 

 tactile sensations. And, in consequence of the v incessant 

 association of the muscular and the tactile sensations, 

 they become so fused together that they are often con- 

 founded under the same name. 



If freedom to move in all directions is the very essence 



