516 Dr. G. Thin on the Anatomy of 



junctival epithelium of the cornea has not been previously removed, the 

 cells of that structure can be recognized amongst the others ; and if the 

 mass under examination has not been too much broken up in manipu- 

 lating, groups of them may be seen -in direct anatomical continuity with 

 long narrow flat cells, which belong to the elements that have been for 

 the first time brought to light by the potash solution. 



But the cells of the anterior or surface-epithelium form a very small 

 proportion of the number. The smallest piece that can be removed by 

 the needle from a cornea which, before being put into the solution, has 

 had this epithelium scraped off and Descemet's membrane removed, shows 

 under the microscope a multitude of cells. Of the branched corpuscles, 

 the fibrillary substance, and nerves, not a trace is visible. 



The form of these cells is so various that it would be difficult to con- 

 struct a series of types under which every individual cell could be 

 brought. They seem in their development to have assumed any modifi- 

 cation of form that is necessary to enable them to fit accurately the 

 cavities and fibrillary bundles to which they are applied. 



Those whose outlines do not permit their being accurately described as 

 belonging to a strictly denned type, are many of them somewhat qua- 

 drangular or triangular in form, or club-shaped, with a short or long 

 projecting process. Of fixed and definite types are long narrow rods, 

 ending obliquely at the point, and oblong cells intersected at one end by 

 a notch, which receives the extremities of two of the long cells that lie 

 parallel to each other. 



I do not attempt to give an exhaustive account of the various forms 

 assumed by these cells. A better idea than can be given by any de- 

 scription will be got by an examination of figs. 1, 2, 3, Plate VIII,, in 

 which many of them are represented ; but an examination of the first 

 prepared cornea will show that there are many forms and modifications 

 which have not been drawn. 



The cells are granular in appearance, with sharp clear outlines. The 

 terminal surfaces of the long cells can often be seen to be finely serrated ; 

 and so closely do they fit each other at these points, that sometimes a 

 high magnifying-power is necessary to discover the suture-like line by 

 which the junction is indicated. 



The nuclei of all the cells have nearly the same length, but in the 

 narrower cells the nucleus is often much compressed transversely. 



The long cells are many of them 0*09 millim. long and from O006- 

 0-003 millim. broad ; the shorter cells are broader. Those 0-06 millim. 

 long are generally about 0*009 millim. broad. A length of 036 millim., 

 with a breadth of about 0-015 millim. is common ; others are 0*03 millim. 

 long and 0*012 millim. broad. 



I have chiefly examined the cells in the cornea of the ox, sheep, and frog, 

 and have found no important differences either in shape or arrangement. 



In examining portions of the cornea which have been as little dis- 



