CONTENTS ix 



PAGE 



8. Dioptric importance of the iris. 9. Mechanism and innervation of 

 pupil in accommodation ; theory of pupil-reflexes. 10. Absorption and 

 reflection of light in the eye ; ophthalmoscopy and skiascopy. Biblio- 

 graphy. 



CHAPTER VII 



RETINAL EXCITATION AND VISUAL STIMULATION . . . 330 



1. Histological structure of retina. 2. Direct and indirect vision 

 (blind spot, retinal elements the receptors of light-stimuli). 3. Ob- 

 jective phenomena of retinal stimulation (visual purple, migration of 

 pigment, contraction of epithelial cells and inner segment of cones, 

 electromotive phenomena). 4. Colour vision ; effects produced by 

 different kinds of luminous radiation ; limits of their visibility. 5. 

 Visual acuity ; phases of visual sensations ; positive and negative after- 

 images. 6. Retinal adaptation to light and darkness ; sensibility of 

 central and peripheral regions of retina to day vision and twilight 

 vision (photopia and scotopia). 7. Achromatic and chromatic percep- 

 tions in relation to intensity of light stimulus and retinal adaptation to 

 light and darkness. 8. Duplicity theory of functions of rods and cones. 

 9. Colour mixtures ; complementary colours. 10. Colour contrast ; 

 successive and simultaneous. 11. Theories of achromatic and chromatic 

 vision. 12. Colour blindness ; partial and total. Bibliography. 



CHAPTER VIII 



OCULAR MOVEMENTS AND VISUAL PERCEPTIONS . . . 388 



1. Articulation of eyeball in its socket ; its external muscles ; its 

 movements and possible positions. 2. Isolated and associated move- 

 ments of its muscles. 3. The innervation and co-ordination of the eye- 

 movements. 4. Simple binocular vision and the horopter. 5. Di- 

 plopia. 6. Conflict between the visual images of both eyes and the 

 phenomena of binocular contrast. 7. Spatial perception in monocular 

 and binocular vision. 8. Stereoscopic binocular vision ; the stereo- 

 scope. 9. Psycho-physical processes on which visual perceptions and 

 representations depend ; relativity of our judgments of size, distance 

 and form ; optical illusions and visual hallucinations. 10. Protective 

 apparatus of the eye. 11. Origin of the aqueous humour. Bibliography. 



CHAPTER IX 



PSYCHO-PHYSICAL PHENOMENA OF CONSCIOUSNESS AND SLEEP . 437 



1. The range of mental life includes unconscious as well as conscious 

 processes. 2. States of complete and incomplete consciousness. 3. 

 Subconscious activity ; its great importance in relation to conduct and 



