THE PERCEPTIOiS OF SPACE. 199 



because we have ingrained with them in our imagination a 

 movement on a surface simultaneously felt. 



" Thus whenever we breathe there is a contraction of the muscles 

 of the ribs and the diaphragm. Since we see the chest expanding, we 

 know it as a movement and can only think of it as such. But the dia- 

 phragm itself is not seen, and consequently by no one who is not physi- 

 ologically enlightened on the point is this diaphragm thought of in 

 movement. Nay, even when told by a physiologist that the diaphragm 

 moves at each breathing, every one who has not seen it moving down- 

 ward pictures it as an upward movement, because the chest moves 

 upward." * 



A personal experience of my own seems strongly to cor- 

 roborate this view. For years I have been familiar, during 

 the act of gaping, with a large, round, smooth sensation in 

 the region of the throat, a sensation characteristic of gap- 

 ing and nothing else, but which, although I had often 

 wondered about it, never suggested to my mind the motion 

 of anything. The reader probably knows from his own 

 experience exactly what feeling I mean. It was not till one 

 of my students told me, that I learned its objective cause. 

 If we look into the mirror while gaping, we see that at the 

 moment we have this feeling the hanging palate rises by 

 the contraction of its intrinsic muscles. The contraction 

 of these muscles and the compression of the palatine mu- 

 cous membrane are what occasion the feeling ; and I was 

 at first astonished that, coming from so small an organ, 

 it could appear so voluminous. Now the curious point is 

 this — that no sooner had I learned by the eye its objective 

 space -significance, than I found myself enabled mentally to 

 fed it as a movement upwards of a body in the situation of 

 the uvula. When I now have it, my fancy injects it, so to 

 speak, with the image of the rising uvula ; and it absorbs 

 the image easily and naturally. In a word, a muscular 

 contraction gave me a sensation whereof I was unable dur- 

 ing forty years to interpret a motor meaning, of which two 

 glances of the eye made me permanently the master. To my 

 mind no further proof is needed of the fact that muscular 

 contraction, merely as such, need not be perceived directly 

 as so much motion through space. 



* Problems of Life and Miud, prob. vi. chap. iv. § 45. 



