THE INTERIOR OF THE EYE
For the study of the interior of the eye and its contents in situ either a fresh or a hardened eye will do; a hardened eye is preferable. In the dissection for isolating the hyaloid membrane, vitreous, lens, and other parts, the anterior and posterior halves of the evacuated eye may be separated entirely, and each half studied. However, the choroid and the retina will be more or less mutilated, and the vitreous and other parts will be removed. The absence of these parts will prevent one from receiving a definite idea of their anatomical relationships. Therefore, it is better to work with an entire and complete eye.
Fig. 9—Showing method of cutting eye into anterior and posterior sections with safety-razor blade.
Remove all the muscles and fatty tissues from the outside of the globe; then cut it in half through the equator, thus dividing it into an anterior and a posterior half. The cutting of the sclerotic, as well as the underlying tissues and the vitreous, should be done with the large scissors; using a knife or scalpel will tend to disturb the positions of those tissues or so tear them that they will not be of much use for purposes of study. An ordinary safety-razor blade makes an excellent instrument for separating the eye into two halves, because it cuts through the tissues without tearing them in any way. ([Fig. 9].) The rather dark colored, viscid fluid that escapes when the eye is halved is the perichoroidal lymph, not the aqueous, as is sometimes stated.