THE EYE. 239 



ward, five layers: I. A stratified layer of epithelial 

 cells the anterior corneal epithelium consisting of 

 cells resembling in general form and arrangement 

 those of the epidermis ; that is, we have in the 

 deepest layer, cylindrical cells, passing over into 

 polyhedral, and these into flattened cells at the 

 surface ; 2. The anterior epithelium rests on a 

 dense transparent membrane, called the anterior 

 basal membrane, or lamina elastica anterior, which 

 is composed of closely packed fibrillae ; 3. The body 

 of the cornea substantia propria cornece is com- 

 posed of connective tissue whose characteristics we 

 have already studied ; 4. Lying closely upon the 

 posterior surface of the last layer, is a thin, appar- 

 ently structureless membrane the membrane of 

 Descemet or lamina elastica posterior upon which 

 lies : 5. A single layer of flattened polyhedral cells, 

 called the endothelium of Descemet. 



Except at its extreme periphery, the cornea con- 

 tains no blood-vessels. Nerves, on the other hand, 

 are very abundant. These, in larger and smaller 

 trunks, enter the cornea at the periphery, and divid- 

 ing and subdividing, break up into bundles of 

 extremely delicate fibrils, some of which are dis- 

 tributed to the superficial, others to the deep, layers 

 of the cornea. These fibrils form extraordinarily 

 delicate and intricate plexuses, and are finally 

 resolved into the ultimate nerve-fibrils which, often 

 finely beaded, pass off to their terminations. The 



