THE EYE 



89 



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

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

 i. The aqueous humour : the transparent watery 

 fluid filling the anterior chamber of the eye 

 and escaping when the cornea is removed. 

 ii. The lens. 



CP 



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 ; 8, sclerotic ; SL, suspensory liga- 

 ment ; Y, yellow spot. (The yellow spot is absent from a beast's eye. ) 



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 round for a distance of about half an 

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

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



