CONTENTS OF PART IV. 



BOOK III. (continued). 



CHAPTER III. 

 SIGHT. 



SECTION I. 



ON THE GENERAL STRUCTURE OF THE EYE, AND ON THE FORMATION 

 OF THE RETINAL IMAGE. 



PAGE 



702. Dioptic Mechanisms and Visual Impulses . 1 



703. The General Structure of the Eye. The Formation of the Retinal 



Image 2 



704. A simple Optic System : its Cardinal Points. The Refractive Sur- 



faces and Media of the Eye 6 



705. The Optic Constants of the Eye. The Diagrammatic Eye ... 9 



706. The Paths of the Rays of Light through the Eye 10 



707. The Retinal Image in relation to the Sensations excited by it . . 12 



SECTION II. 

 THE FACTS OF ACCOMMODATION. 



708. The Eye can accommodate for far and near Objects ; far and near 



Limits of Accommodation , 13 



709. Schemer's Experiment 14 



710. Emmetropic, Myopic, Hypermetropic, and Presbyopic Eyes . . 16 



711. The Changes observed in the Eye during Accommodation ... 17 



