TWENTY-FOURTH LECTURE. 



THE ORGANS OF SENSE, CONTINUED. — THE EYE. 



We have still to mention the termination of the optic 

 nerve. In doing this we must of course draw into the circle 

 of our discussion the entire eye, that magnificent and won- 

 derful organ which is so important for the physician. Never- 

 theless, in consequence of its extremely complicated structure, 

 we can only present a cursory incomplete description. 



The eyeball (Fig. 199) presents first an external capsular 



Fig. 199. — Transverse section of the eye ; a, sclerotica ; b, cornea ; c, conjunctiva ; d, circulus 

 venosus iridis ; e, choroid, with the pigment layer of the retina ; f, ciliary muscle ; g, ciliary process ; 

 It. iris : z, optic nerve ; i', colliculus opticus ; k, ora serrata retinae ; /. crystalline lens ; m, tunica 

 Descemetii ; «, membrana limitans interna of the retina ; o, membrana hyaloidea ; j>, canalis 

 Petiti ; q, macula lutea. 



system ; the posterior, opaque, greater portion is formed by 

 the sclerotic {a), while the anterior, smaller, transparent seg- 



