• In the rabbit, cells coalesce to repair a damaged corneal endothelial layer. Clinical specular microscopy showed that this phenomenon also occurs in human beings. The resulting endothelial cells are large, irregularly shaped, and multinucleated. They are quite different in their specular microscopic appearance from corneal endothelial cells seemingly undergoing mitosis, which was observed in a successful penetrating keratoplasty and which represents another apparent mode of repair. Additional evidence for coalescence of endothelial cells is derived from evaluation of histograms of cell size v age that have been published previously.