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HANDBOOK OF PHYSIOLOGY. 



ing of seven or eight layers of cells, of which the superficial ones are 

 flattened and scaly, and the deeper ones more or less columnar. Imme- 

 diately beneath this is the anterior elastic lamina of Bowman, which 



Fig. 408. Horizontal preparation of cornea of frog ; showing the network of branched cornea- 

 corpuscles. The ground substance is completely colorless. X 400. (Klein.) 



differs, only in being more condensed tissue, from the general structure 

 of the cornea or cornea proper. 



This latter tissue, as well as its epithelium is, in the adult, com- 

 pletely destitute of blood-vessels; it consists of an intercellular ground- 

 substance of rather obscurely fibrillated flattened bundles of connective 

 tissue, arranged parallel to the free surface, and forming the boundaries 

 of branched anastomosing spaces in which the cornea-corpuscles lie. 

 These branched cornea-corpuscles have been seen to creep by amoeboid 



Fig, 409. Surface view of part of lamella of kitten's cornea, prepared first with caustic 

 potash and then with nitrate of silver. (By this method the branched cornea-corpuscles with 

 their granular protoplasm and large oval nuclei are brought out.) X 450. (Klein and Noble 

 Smith.) 



movement from one branched space into another. At its posterior sur- 

 face the cornea is limited by the posterior elastic lamina, or membrane 

 of Descemet, similar in structure to the anterior elastic lamina, the inner 

 layer of which consists of a single stratum of epithelial cells (fig. 410, d). 

 Nerves. The nerves of the cornea are both large and numerous: they 



