PKOGEESS OF MICROSCOPICAL SCIENCE. 241 



groups of them may bo 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 i^otash 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 cor- 

 puscles, 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 modi- 

 fication 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 defined type, are many of them somewhat 

 quadi'angular or triangular in form, or club-shaj^ed, 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 description 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-j)repared 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 0*006-0 -003 millim. broad ; the shorter 

 cells are broader. Those 0*06 millim. long are generally about 

 0*009 millim. broad. A length of 0*36 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 disturbed as is consistent with the main- 

 tenance of transparency, grouf)s of cells are foitud massed together 

 in situ, as they have been left by the dissolving out of the fibrillary 

 substance by the potash: these are found chiefly in two forms. 

 Transverse masses of the anterior epithelium are foimd sutured to 

 long narrow cells, which sometimes seem to join them at an angle. 

 Further, flat quadrangular masses of a single layer of cells are found 

 formed in the following manner : — Of two opposite sides the external 

 rows are formed of more or less rounded and angular cells, to which 

 are joined long narrow cells that lie parallel to each other. Those 



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