92 DISSECTION OF THE EYE. 



3. The Choroid Coat lying under the sclerotic is 

 much thinner and very darkly pigmented. Beneath 

 the line of junction of the sclerotic and cornea the 

 choroid passes-into the iris. 



Pinch tip a bit of the choroid zvith the forceps and 

 snip it off with scissors. From this opening pull or 

 dissect off the choroid from the lahitish underlying 

 retina. 



4. The Retina will be exposed as a delicate opaque 

 membrane lying upon the vitreous humor. 



5. The Vitreous Humor. Pull off the retina w^ith 

 a pair of forceps. The vitreous humor will be seen as 

 a transparent gelatinous mass filling up the cavity Of 

 the eyeball. It is enclosed in a delicate membrane, 

 the hyaloid membrane. Through the window thus 

 made the interior of the eyeball can be seen. 



To get a better view of the interior ciit through the 

 eyeball in the equatorial plane with a pair of scissors, 

 dividing it ittto an anterior and a posterior half. 



POSTERIOR HALF. 



6. The Retina. Notice the way in which the retina 

 curls away from the choroid. One of the layers of 

 the retina, the pigmentary epithelium, is left in con- 

 nection with the choroid. 



7. The Optic Disc. The point of entrance of the 

 optic nerve is seen as a small white oval area, com- 

 posed of the nerve-fibres of the optic nerve, and not 

 having the structure of the retinal membrane. It is 

 the blind spot of the eye. The blood-vessels of the 

 retina enter through the optic nerve and can be seen 

 radiating from the middle of the optic disc. The 

 retina can be torn off easily with forceps as far as the 

 optic disc, where it is firmly attached. 



