94 DISSECTION OF THE EYE. 



Divide this portion of the eye into a right and e 

 left half by a cut along the vertical meridian, 



12. Junction of the Choroid and Iris. Along the cut 

 edge of one of these halves notice the relations of the 

 choroid, ciliary processes, and iris. The iris is direct- 

 ly continuous with the choroid, and along the line of 

 junction of the two the part of the choroid coat known 

 as the ciliary processes is partly free, projecting some- 

 what toward the interior of the eye. 



13. The Canal of Schlemm. Find the point of 

 junction of choroid and iris. Between this and the 

 sclerotic where it joins the cornea is a rather con- 

 spicuous canal running circularly round the eyeball. 

 Insert a bristle and follow its course. 



14. The Ciliary Muscle. At the posterior margin 

 of the canal of Schlemm the choroid coat is firmly 

 attached to the sclerotic by an oblique band of whit- 

 ish fibres, the radial fibres of the ciliary muscle. 

 These fibres belong to the class of involuntary muscle- 

 fibres. When they contract they pull forward the 

 choroid coat and slacken the suspensory ligament, al- 

 lowing the lens to become more convex. 



For the following dissection a fresh eye should be 

 used. Do not clean off the muscles, etc., but fasten the 

 eye to the beeswax by the aid of pins so that the cornea 

 faces directly upwards and projects somewhat above 

 the level of the zuater in the pan. 



15. The Aqueous Humor and Anterior Chamber. 

 Cut through the cornea at its junction with the scle- 

 rotic, and dissect it off completely. The liquid that 

 escapes is the aqueous humor. It fills up the space 

 between the cornea and the iris known as the anterior 

 chamber of the eye. 



