THE EYE 



89 



from its junction with the sclerotic : remove the cornea : take care 

 not to squeeze the eye, or the lens will he driven out instantly : note : 



i. The a4ueous humour : the transparent watery fluid 

 filling the anterior cliamber of the eye, and 

 escaping when the cornea is removed. 



ii. The lens. 



Fig. 17. — ^A diagrammatic section through the human eye passing 

 through the centres of the cornea and lens, and through the yellow 

 spot and point of entrance of the optic nerve. 



A, anterior chamber ; Ar, central artery of retina ; B, blind spot ; 

 C, cornea ; Ch, choroid ; CP, ciliary processes ; H, hyaloid membrane, 

 enclosing the vitreous humour ; I, iris ; L, lens ; O, optic nerve ; 

 p, posterior chamber ; R, retina ; s, sclerotic ; SL, suspensory liga- 

 ment ; Y, yellow spot. 



3. Pass the handle of a scalpel under the cut edge of the cornea, 

 between it and the iris, and carefully separate the sclerotic from 

 the choroid the whole way rov/nd for a distamce of about half an 

 itiich beyond the edge of the cornea. Make four radial cuts, equi- 

 distant from one another, tkrough the margin of the cornea and 



