THE ANTERIOR HALF
The anterior half will show the lens in situ, the ciliary processes, the posterior aspects of the iris and the lens, the corona ciliaris, the orbicularis ciliaris, and the ora serrata. ([Fig. 16].) If the eye has been cut in two too far forward of its equator, the ora serrata will not be present. The ciliary processes and posterior aspect of the lens may be seen to better advantage when the anterior half of the vitreous is removed. This is done with the dull-pointed tweezers, by catching hold of the vitreous at any part of its free or cut margin, and stripping it off both the ciliary processes and the lens, using a prying, pulling movement to do so. ([Fig. 17].) The two layers of the pigment cells, pars ciliaris retinae, which cover the inner surface of the processes, may be removed by picking them away carefully with the tweezers. The processes then will be seen to be a whitish color. The pupillary edge of the iris rests upon the capsule of the lens, but the nearer the approach is to the choroidal edge the farther the iris is from the lens; thus are formed the anterior and the posterior chambers of the eye. The dissection of the sagittal section of the eye, explained further on, will show these two chambers in section. One will gain a much clearer conception of their construction in that section than in the “anterior half” specimen.
Fig. 17—Anterior half, showing how to pull off vitreous. ([Page 49].)
Now, remove the lens, using the point of the scalpel to cut through the suspensory ligament close to the lens. When this has been done there will be seen in the anterior chamber a thin, watery liquid—the aqueous humor.
The corona ciliaris and orbicularis ciliaris may be better seen and studied if viewed through a hand lens.