viii CONTENTS. 



SECTION III. 

 ON THE STRUCTURE OP THE INVESTMENTS OF THE KETINA. 



PAGE 



712. The Sclerotic Coat 1159 



713. The Choroid Coat 1159 



714. The Ciliary processes . . . . . . . .1161 



715. The Iris 1162 



716. The Cornea . . . 1163 



717. The Ciliary Zone 1164 



718. The Ciliary Muscle . . . . . . . . . . 1166 



719. The Lens . . . 1166 



720. The Vitreous Humour and the Suspensory Ligament . . . 1167 



SECTION IV. 



THE MECHANISM OF ACCOMMODATION AND THE MOVEMENTS OF 

 THE PUPIL. 



721. The mechanism for changing the anterior curvature of the lens . 1169 



722. The evidence that such a mechanism does effect the result . . 1170 



The Movements of the Pupil. 



723. Circumstances leading to constriction and to dilation of the pupil . 1172 

 724. How constriction and dilation are brought about . . . .1172 



725. The nerves supplying the pupil 1173 



726. Constriction a reflex act by means of the optic and oculo-motor 



nerves 1175 



727. Changes in the pupil through the action of the cervical sympathetic 



nerve 1178 



728. The nature of the dilating mechanism 1179 



729. Direct action of drugs and other agencies on the pupil . . . 1181 



730. The nervous mechanism of accommodation . . . . . 1183 

 731. The association of the movements of accommodation and the 



movements of the pupil 1184 



SECTION V. 

 IMPERFECTIONS IN THE DIOPTRIC APPARATUS. 



732. Imperfections of accommodation 1185 



733. Spherical aberration 1186 



734. Astigmatism 1186 



735. Chromatic aberration . . . 1188 



736. Entoptic phenomena . . 1189 



