268 PSYCHOLOGY. 



pare non-parallel figures as it now is to judge of those 

 which are parallel.* Those which it took the same amount 

 of movement to traverse would be equal, in whatever direc- 

 tion the movement occurred. 



GENE3RAL SUMMARY. 



With this we may end our long and, I fear to many- 

 readers, tediously minute survey. The facts of vision form 

 a jungle of intricacy ; and those who penetrate deeply into 

 physiological optics will be more struck by our omissions 

 than by our abundance of detail. But for students who 

 may have lost sight of the forest for the trees, I will re- 

 capitulate briefly the points of our whole argument from 

 the beginning, and then proceed to a short historical survey, 

 which will set them in relief. 



All our sensations are positively and inexplicably exten- 

 sive wholes. 



The sensations contributing to a-pace-perception seem 

 ■exclusively to be the surface of skin, retina, and joints. 

 * Muscular ' feelings play no appreciable part in the genera- 

 tion of our feelings of form, direction, etc. 



The total bigness of a cutaneous or retinal feeling soon 

 becomes subdivided by discriminative attention. 



Movements assist this discrimination by reason of the 

 peculiarly exciting quality of the sensations which stimuli 

 moving over surfaces arouse. 



Subdivisions, once discriminated, acquire definite rela- 

 tions of position towards each other within the total space. 

 These 'relations' are themselves feelings of the subdivis- 

 ions that intervene. When these subdivisions are not the 

 seat of stimuli, the relations are only reproduced in imagi- 

 nary form. 



The various sense-spaces are, in the first instance, inco- 

 herent with each other ; and primitively both they and 

 their subdivisions are but vaguely comparable in point of 

 bulk and form. 



The education of our space-perception consists largely 

 of two processes — reducing the various sense-feelings to a 



* Cf. Heriug in Hermann's Handb. der Physiol., iii. 1, pp. 553-4. 



