Connective Tissue, Nerve, and Muscle. 517 



turbed as is consistent with the maintenance of transparency, groups of 

 cells are found massed together in situ, as they have been left by the dis- 

 solving out of the fibrillary substance by the potash : these are found 

 chiefly in two forms. Transverse masses of the anterior epithelium are 

 found 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 from each 

 side respectively meet in the centre, where they join. The remaining 

 sides of the quadrangle are formed by a side view of these various cells, 

 where they have been detached from the adjoining ones in the breaking 

 down of the cornea mass. 



The coincidence between the breaclth of the long narrow cells and the 

 fibrillary bundles of the cornea-substance, as seen when prepared by the 

 ordinary methods, is evident, the continuous planes formed by their junc- 

 tion indicating that they form layers between which it is enclosed. 

 According to this view, the ground-substance is everywhere encased in 

 a sheath of cellular elements. 



Bowman's corneal tubes I believe to include both the straight canals 

 described in the paper above referred to and the spaces between the 

 long cells widened by injection, chiefly the latter. 



Although I have nothing to add to the description of the mode of pre- 

 paration which I have already given, I must state that there are conditions 

 of success, as to the nature of which I have not yet come to a definite con- 

 clusion. Sometimes the same solution, applied at the same temperature 

 to different cornese, succeeds in one and fails in another, and sometimes 

 a solution prepared with every precaution has failed to afford me any 

 result. The two essential conditions to success are complete saturation 

 and temperature. I have never succeeded with a temperature above 

 120, nor with one below 102 ; and so sensitive is the solution to mois- 

 ture, that preparations sealed in it with asphalt seldom keep longer than 

 one or two days, except in very dry weather. On a damp day I have 

 known a successful preparation left on the object-glass disappear in six 

 hours. The corneal mass may be kept unaltered for at least some weeks 

 in the solution by running sealing-wax round the stopper of the bottle. 



A perfectly successful preparation shows nothing but the cells. Un- 

 successful preparations, especially those prepared with too hot solution, 

 show globular masses unlike any anatomical element ; others, especially 

 those prepared at too low a temperature or with imperfect saturation, 

 show masses of hexagonal crystals like those of cystin. 



To sura up, I believe that there exists in the cornea : 



I., the fibrillary ground-substance, which is pierced by straight canals 

 and honeycombed with cavities ; 



2n2 



