THE PERCEPTION OF SPACE. 195 



But if the joint-feelings are directions and extents, 

 standing in relation to each other, the task of association in 

 interpreting their import in eye- or skin-terms is a good deal 

 simplified. Let the movement he, of a certain joint, deiive 

 its absolute space-value from the cutaneous feeling it is 

 always capable of engendering ; then the longer movement 

 ahcd. of the same joint will be judged to have a greater 

 space-value, even though it may never have wholly merged 

 with a skin-experience. So of differences of direction : so 

 much joint-difference = so much skin-difference ; therefoie, 

 more joint-difference = more skin-difference. In fact, the 

 joint-feeling can excellently serve as a map on a reduced scale, of 

 a reality ivhich the imagination can identify at its pleasure 

 with this or that sensible extension simultaneously known in 

 some other way. 



When the joint-feeling in itself acquires an emotional 

 interest, — which happens whenever the joint is inflamed 

 and painful, — the secondary suggestions fail to arise, and 

 the movement is felt where it is, and in its intrinsic scale ol 

 magnitude.* 



The localization of the joint-feeling in a space simulta- 

 neously known otherwise (i.e. to eye or skin), is what is 

 commonly called the extradition or eccentric projection of the 

 feeling. In the preceding chapter I said a good deal on this 

 subject ; but we must now see a little more closely just what 

 happens in this instance of it. The content of the joint- 

 feeling, to begin with, is an object, and is in itself a place. 

 For it to be placed, say in the elbow, the elbow as seen or han- 

 dled must already have become another object for the mind, 



* I have said hardly anything about associations with visual space in 

 the foregoing account, because 1 wished to represent a process which the 

 blind and the seeing man might equally share. It is to be noticed that 

 the space suggested to the imagination when the joint moves, and pro- 

 jected to the distance of the finger-tip, is not represented as any specific 

 skin-tract. What the seeing man imagines is a visible path; what the blind 

 man imagines is rather a generic image, an abstraction from many skin- 

 spaces whose local signs have neutralized each other, and left nothing but 

 their common vastness behind. We shall see as we go on that this generic 

 abstraction of space-magnitude from the various local peculiarities of feel- 

 ing which accompanied it when it was for the first time felt, occurs on a 

 considerable scale in the acquired perceptions of blind as well as of seeing 

 men. 



