ENDOTHELIUM OF THE CORNEA. 4^1 



four rows, at distances from each other that are about equal to 

 the diameter of their bases. In old people they are about O02 of 

 a millimeter wide at their base, and O'Ol of a millimeter high, 

 and form a broad zone. In rare cases they extend as far as the 

 centre of the cornea (H. M tiller). 



The connections formed by the membrane of Descemet at its 

 border will be 'subsequently considered. 



THE ENDOTHELIUM OF THE MEMBRANE OF DESQEMET. 

 Internal Epithelium of the Cornea. 



The endothelium of the membrane of Descemet consists, in 

 the eye of Man and of adult animals, of a layer of polygonal 

 cells, having a diameter of O025 of a millimeter.* The cells 

 have a flattened appearance, and possess round nuclei, with 

 a diameter of O'OOS of a millimeter. t In perfectly fresh eyes 

 the endothelium may be stripped off in the form of a continuous 

 membrane. This layer of cells situated at the back of the 

 cornea is not to be included amongst the true epithelia, but 

 amongst the endothelia.J 



In the endothelial cells of the membrane of Descemet of the 

 irritated cornea of the Frog, Klebs observed the occurrence of 

 a series of alterations of form, which under certain circumstances 

 are as lively as those of the lymph corpuscles, and lead to 

 detachment of the cells. Norris and Strieker]] also saw move- 

 ments take place in the endothelial cells of the membrane of 

 Descemet in inflamed cornese, and state that they observed an 

 increase in the number of the nuclei, and a proliferation of the 

 cells. If the freshly excised and healthy cornea of the Frog 

 be moistened with aqueous humour as rapidly as possible, be 

 brought under the microscope, and the endothelium of the 

 membrane of Descemet be examined whilst in accurate focus, 

 it will frequently appear as if composed of two kinds of 



* Henle, loc. tit., p. 607. 

 t Henle, loc. cit. 



4. His, Haute und Hohlen des Korpers (Membranes and cavities of the 

 body), p. 18. -Basel, 1865. 



Centmlblatt fur die, medicin. Wissenschaften, 1864, pp. 513 510. 

 || Norris and Strieker, loc. cit., pp. 16 and 17. 



