THE EYE. 93 
1. Dissect off the muscles of the eyeball and the fat which sur- 
rounds the optic nerve. note :— 
i. The shape of the eyeball. 
ii. The sclerotic, covering about five-sixths of the 
eyeball ; tough, white, and opaque. 
iii, The cornea: covering the outer sixth of the 
eyeball: circular, transparent: continuous at 
its margin with the sclerotic : more convex than 
the sclerotic. 
iv. The conjunctiva: a delicate epithelial layer, cover- 
ing the front of the cornea and part of the 
sclerotic. 
vy. The iris: a pigmented ring seen through the 
cornea. 
vi. The pupil: the central aperture surrounded by 
the iris. 
vii. The optic;nerve: piercing the sclerotic at the back 
of the eye. 
2. Cut all round the cornea close to its margin with fine scissors : 
remove the cornea: 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. 
3. Make four radial cuts equidistant from one another through 
the margin of the cornea and the sclerotic, taking care not to injure 
the deeper parts ; and extend the cuts back towards the optic nerve. 
Carefully peel off the four flaps into which the sclerotic is now 
divided from the underlying black choroid coat: turn them down, 
and pin them to the dissecting board so as to fix the eye with the 
iris upwards: note :— 
i. The ciliary muscle: a whitish ring of unstriped 
muscle connecting the outer margin of the iris 
with the junction of the cornea and sclerotic: 
this must be detached with the handle of the 
scalpel to allow the flaps of the sclerotic to be 
turned back. 
