162 PSYCHOLOGY. 



invincibly attract the fove?e to themselves. If we contem- 

 plate a blank wall or sheet of paper, we always observe in 

 a moment that we are directly looking at some speck upon it 

 which, unnoticed at first, ended by 'catching our eye.' Thus 

 whenever an image falling on the point P of the retina excites 

 attention, it more habitually moves from that point towards the 

 fovea than in any one other direction. The line traced thus by 

 the image is not always a straight line. When the direction 

 of the point from the fovea is neither vertical nor horizon- 

 tal but oblique, the line traced is often a curve, with its con- 

 cavity directed upwards if the direction is upwards, down- 

 wards if the direction is downwards. This may be verified 

 by anyone who will take the trouble to make a simple ex- 

 periment with a luminous body like a candle-flame in a dark 

 enclosure, or a star. Gazing first at some point remote 

 from the source of light, let the eye be suddenly turned full 

 upon the latter. The luminous image will necessarily fall 

 in succession upon a continuous series of points, reaching 

 from the one first affected to the fovea. But by virtue of 

 the slowness with which retinal excitements die away, the 

 entire series of points will for an instant be visible as an 

 after-image, displaying the above peculiarity of form ac- 

 cording to its situation.* These radiating lines are neither 

 regular nor invariable in the same person, nor, probably, 

 equally curved in dijBferent individuals. We are incessant- 

 ly drawing them between the fovea and every point of the 

 field of view. Objects remain in their peripheral indistinct- 

 ness only so long as they are unnoticed. The moment we 

 attend to them they grow distinct through one of these mo- 

 tions — which leads to the idea prevalent among uninstructed 

 persons that we see distinctly all parts of the field of view 

 at once. The result of this incessant tracing of radii is that 

 whenever a local sign P is aivakened by a spot of light falling 

 upon it, it recalls forthtvith, even though the eyeball be unmoved, 

 the local signs of all the other points lohich lie between P and 

 the fovea. It recalls them in imaginary form, just as the 

 normal reflex movement would recall them in vivid form ; 

 and with their recall is given a consciousness more or less 



* These facts were first noticed by Wundt: see his Beitrage, p. 140, 203. 

 See also Lamansky, Pfliiger's Archiv, xi. 418. 



