556 SHINICHI MATSUMOTO 



irregular. This was most marked when active cells on the border, 

 showing unusual protoplasmic activities, tore themselves loose 

 from their connection. Similar conditions, however, were often 

 to be noticed in the actively mobile epithelial layer growing out 

 into firmly clotted plasma. In the epithelial movement on the 

 endothelial surface, such a condition but rarely occurred; as a 

 rule, the cells moved more uniformly, showing a smooth advanc- 

 ing border. 



In other instances small pieces of cover-glass or celloidin mem- 

 brane were placed on the endothelial surface and pressed against 

 it, so that a certain portion or the whole of this surface, 

 which is a favorable support for moving cells, was covered. 

 In these cases the epithelium was also seen to move over the 

 celloidin or glass, if they were suitably mounted and the cells 

 were not injured. Where the cell movemelit on such artificial 

 supports failed, examination proved that the placing of the 

 membrane was not suitable; thus, by control of pressure, it was 

 possible to direct the moving cells to these artificial surfaces, 

 though this was not always an easy matter. At any rate, it is 

 an established fact that the epithelium is able to creep on objects 

 of such nature that chemical influences are excluded. 



h. On dead cornea. If in a part of an explanted piece of cornea 

 an epithelial defect existed, it was seen that the epithelial cells 

 were able to cover the spot, spreading out from all edges, prac- 

 tically with the same rapidity as on the endothelial surface. 



The same was true of a spot which had been killed by touching 

 it with a heated needle. The cells injured by the latter procedure 

 became round and detached, and the growing epithelium crept 

 beneath them along the surface of the killed tissue. 



Preparations were made of large strips of corneal tissue (about 

 2x4 mm.), across the center of which a sharply defined epithelial 

 defect was produced, after which one half of the remaining corneal 

 tissue was killed by means of a heated needle, making the tissue 

 surface look opaque and wrinkled. In such preparations it was 

 seen that the epithelial movement over the wound occurred uni- 

 formly, covering both the live and the dead tissue with the same 

 rapidity. 



