THE PERCEPTION OF SPACE. 193 



of angular rotation. No active muscular contraction took 

 place. The minimal felt amounts of rotation were in all cases 

 surprisingly small, being much less than a single angular de- 

 gree in all the joints except those of the fingers. Such dis- 

 placements as these, the author says (p. 490), can hardly be 

 detected by the eye. The point of application of the force 

 which rotated the limb made no difierence in the result. 

 Rotations round the hip-joint, for example, were as deli- 

 cately felt when the leg was hung by the heel as when it 

 was hung by the thigh whilst the movements w^ere per- 

 formed. Anaesthesia of the skin produced by induction-cur- 

 rents also had no disturbing effect on the perception, nor 

 did the various degrees of pressure of the moving force 

 upon the skin affect it. It became, in fact, all the more 

 distinct in proportion as the concomitant pressure-feelings 

 were eliminated by artificial anaesthesia. When the joints 

 themselves, however, were made artificially anaesthetic the 

 perception of the movement grew obtuse and the angular 

 rotations had to be much increased before they were 23er- 

 ceptible. All these facts prove according to Herr Gold- 

 scheider, that the joint surfaces and these alone are the start- 

 ing point of the impressions by which the movemeiits of our 

 members are immediately perceived. 



Applying this result, which seems invulnerable, to the 

 case of the tracing finger-tip, we see that our perception of 

 the latter gives no countenance to the theory of the mus- 

 cular sense. We indubitably localize the finger-tip at the suc- 

 cessive points of its path by meatis of the sensations ivhich we 

 ■receive from our joints. But if this is so, it may be asked, 

 why do we feel the figure to be traced, not within the joint 

 itself, but in such an altogether different place ? And why 

 do we feel it so much larger than it really is ? 



I will answer these questions by asking another : Why 

 do we move our joints at all ? Surely to gain something 

 more valuable than the insipid joint-feelings themselves. 

 A-nd these more interesting feelings are in the main pro- 

 duced upon the skin of the moving part, or of some other 

 part over which it passes, or iipou the eye. With move- 

 ments of the fingers we explore the configuration of all real 

 objects with which we have to deal, our own body as well as 



