DISSECTION OF EYE. 303 



small piece of board or shingle ; and if it is desirable to turn 

 the eye, it is better to do so by turning the support, as the 

 eye usually sticks to the support, and the dissection may be 

 injured by trying to move it. 



CAUTION. After the eye is opened be careful not to com- 

 press it. If the eye be held in the hand while trying to cut 

 its tough outer coat, the jelly-like contents are easily squeezed 

 out, ruining the dissection. Let the eye rest on the board all 

 the time, and after first cutting through the cornea it is not 

 necessary nor advisable to touch it with the fingers. 



1. Lay the eye on the board, with the cornea uppermost. 

 Hold the eye firmly with the thumb and fingers of one hand ; 

 with the thumb and forefinger of the other hand hold the 

 blade of the scalpel half an inch from its tip ; with a steady 

 motion push the blade horizontally through the cornea, near 

 its edge. 



2. The liquid in the cavity back of the cornea is the 

 Aqueous Humor. 



3. Slightly enlarge the cut horizontally ; then with the 

 forceps take hold of the upper edge of the cut, and with the 

 scissors cut around the margin of the cornea and remove it. 



4. The dark membrane now exposed is the Iris. Pinch the 

 eye slightly at the sides to make the iris show more distinctly. 

 The hole in its center is the Pupil. With the forceps raise the 

 edge of the iris around the margin of the pupil to see that it 

 is here unattached to the structures underneath. Observe the 

 color and markings of the iris. 



5. From one end of the pupil cut outward to the outer 

 margin of the iris ; then cut around its outer margin and re- 

 move it. Observe the color and markings of the posterior 

 surface. 



6. The body now laid bare is the Crystalline Lens. Touch it. 



7. Lay a piece of newspaper close to the eye, on which to 



