THE EYE. 



with a gelatinous substance, the vitreous body, which 

 presents an ill-defined lamellar structure, and some- 

 times contains a variable number of ill-defined more 

 or less granular cells. The vitreous is surrounded 

 by a delicate membrane, called the hyaloid mem- 

 brane, which is closely connected posteriorly with 

 the lining membrane of the retina, and is hardly to 

 be differentiated from it. The hyaloid membrane is 

 thickened and fibrillated over the ciliary processes, 

 where it is called the zonula ciliaris, and a prolonga- 

 tion forward from this constitutes the suspensory 

 ligament of the lens. 



Having thus briefly described the general struc- 

 ture of the eye, it remains for us to consider some 

 of its parts somewhat more in detail ; the scope of 

 this manual will not permit us, however, to make 

 an extended study of all or even any of the struc- 

 tures in the eye ; we shall be obliged to confine 

 ourselves to the more marked structural features of 

 the cornea and sclera, the posterior portions of the 

 choroid and retina, the iris and crystalline lens. 



THE SCLERA. 



The sclera is composed of very closely interwoven 

 connective-tissue fibres, with fine elastic fibres, the 

 latter most abundant near the inner surface. Be- 

 tween the fibres, which have little regularity in their 

 arrangement, lie flat connective-tissue cells, a certain 

 number of which frequently contain pigment-gran- 



