THE PERCEPTION OF SPACE. 135 



the other. Tlie epithet sliar'p given to the acid class would 

 seem to show that to the popular mind there is something 

 narrow and, as it were, streak}-, in the impression they 

 make, other flavors and odors being bigger and rounder. 



The sensations derived fi*om the inward organs are also 

 distinctly more or less voluminous. Repletion and empti- 

 ness, suffocation, jjalpitation, headache, are examples of 

 this, and certainly not less spatial is the consciousness we 

 have of our general bodily condition in nausea, fever, heavy 

 drowsiness, and fatigue. Our entire cubic content seems 

 then sensibly manifest to us as si^ch, and feels much larger 

 than any local pulsation, pressure, or discomfort. Skin 

 and retina are, however, the organs in which the sj)ace- 

 element plays the most active part. Not only does the 

 maximal vastness yielded by the retina surpass that yielded 

 by any other organ, but the intricacy with which our atten- 

 tion can subdivide this vastness and perceive it to be com- 

 posed of lesser portions simultaneously coexisting along- 

 side of each other is without a parallel elsewhere.* The 

 ear gives a greater vastness than the skin, but is consider- 

 ably less able to subdivide it.t 



Noio my first thesis is that this element, discernible in each 

 and every sensation, though more developed in some than in 

 others, is the original sensation of space, out of which all the 

 exact knowledge about space that we afterwards come to 

 have is woven by processes of discrimination, association, 

 and selection. ' Extensity,' as Mr. James Ward calls it,:}: 



* Prof. Jastrow has found that invariably we tend to underestimate the 

 amount of our skin which may be stimulated by contact with an object 

 when we express it in terms of visual space; that is, when asked to mark 

 on paper the extent of skin affected, we always draw it much too small. 

 This shows that the eye gets as much space-feeling from the smaller line as 

 the skin gets from the larger one. C'f. Jastrow : Mind, xi. 546-7; Ameri- 

 can Journal of Psychologj-, iii. 53. 



f Amongst sounds the graver ones seem the most extensive. Stumpf 

 gives three reasons for this : 1) association with bigger causes; 2) wider 

 reverberation of the hand and bod}^ when grave notes are sung; 3) audi- 

 bility at a greater distance. He thinks that these three reasons dispense us 

 from supposing an immanent extensity in the sensation of sound as such. 

 See his remarks in the Tonpsychologie, i. 207-211. 



X Euc^'clopsedia Britanuica, 9th Edition, article Psychology, pp. 46, 53, 



