540 



THP] CORNEA. 



[sect. 224. 



#. 



regarded as existing in the slightest degree; and 2. that between 

 the bundles and lamellae of the cornea there lie an enormous 



number of anastomosing, fusiform 

 and stellate, nucleated cells, the ' cor- 

 puscles of connective tissue/ or ' cor- 

 nea-corpuscles ' of Virchow, which 

 were first noticed by Toynbee in 1841, 

 and afterwards more distinctly by 

 Virchow : cells of these characters 

 are peculiar to undeveloped elastic 

 tissue, and also occur in a more 

 branched form in the sclerotic. It is 

 probably beyond doubt, that the nu- 

 trient fluid, which continually satu- 

 rates the cornea in large quantity, 

 and which can be directly demon- 

 strated by pressing the cornea, is 

 chiefly conducted and distributed 

 further into the interior by the cells 

 in question ; and this view appears 

 to receive confirmation from the 

 fact, that in diseases of the cornea 

 these cells very frequently contain 

 fat-drops, and in exceptional cases, 

 according to Bonders, even pigment 

 m their interior. The corneal tubes, 

 which have been injected by Bowman in the ox and in the human 

 eye, are not to be confounded with cell-networks ; and they are 

 probably to be regarded as artificial enlargements of the small 

 interspaces which normally occur between the elements of the 

 cornea-tissue, and which, on microscopical examination, may occa- 

 sionally be indistinctly recognised. 



The conjunctiva covering of the cornea chiefly consists of a soft, 

 lamellated epithelium, 0'023'" to o - 05o"' thick, whose lower layers 

 of cells are elongated and disposed perpendicularly upon the 

 cornea ; while the middle ones possess rather a roundish form, and 

 pass superiorly into a layer ©"OoS"' to croi'" thick, of soft, nucleated 

 plates (croi'" to 0"0i4'" in size), corresponding to the horny layer 

 of the epidermis. This epithelium becomes dim very soon after 

 death, as also on the addition of water and acetic acid. Beneath 

 it there exists a structureless lamella, first mentioned by Bowman, 

 and named by him the ' anterior elastic lamella ;' this measures 



Perpendicular section of the cornea of 

 the newly-born infant ; magnified 350 

 times, and treated with acetic acid. The 

 epithelium is left out. A. Anterior por- 

 tion of the cornea, a. Anterior struc- 

 tureless lamella ; b. dense layer of small 

 round granules (probably small cells), 

 with a small quantity of fibrous tissue ; 

 c. developed fibrous tissue, with anasto- 

 mosing plasmatic cells. S. Posterior 

 portion of the cornea, c. As above ; d. 

 structureless lamellfl of the membrane of 

 Descemet. 



