THE EYE 



1509 



Structure. — ^The cornea consists of five layers, which are as follows, 

 from before backwards : 



1. The conjtmctival epithelium. 



2. The anterior elastic lamina. 



3. The substantia propria. 



4. The posterior elastic lamina. 



5. A layer of endothelium. 



The eonjunctival epithelium is of the stratified variety, there 

 being not less than five strata of cells, and it is continuous with the 

 epitheUum which covers the free surface of the conjimctiva. The 



1 Stratified Epithelium of 

 / Conjunctiva 



]~~ Membrane of Bowman 

 or Anterior Elastic 

 Lamina 



Substantia Pn^nia 



Posterior Elastic 

 Lamina or 



MemlM^ne of Descemet 



Single Layer of Sc^uamous 



Epithelium linmg 



Descemet's Membrane 



Fig. 626. — Vertical Section of the Cornea (magnified). 



cells of the deepest stratum are columnar ; succeeding to these 

 there are layers of polygonal cells ; and these in turn are overlaid 

 by layers of squamous cells. 



The anterior elastic lamina (Bowman) is probably of the same 

 nature as the fibrous portion of the substantia propria. It is 

 closely connected with the substantia propria, is thin, and contains 

 no corpuscles. 



The substantia propria is composed of modified connective tissue, 

 arranged in bundles which form superimposed laminae. These 

 laminae amount in number to about sixty: The fibres of alternate 

 laminae cross each other at right angles, and at the circumference 

 of the cornea they are continuous with the fibres of the sclerotic. 



