The clinical observation that the iris does not show any evidence of regeneration of its tissue elements following aseptic iridectomy has never been satisfactorily explained. Up to date there have been very few studies on the healing process of the human iris and only little experimental work on this subject in animals. Daniel (1944) studied the healing process following experimental iridectomy in rabbits and concluded that the iris did not show any tendency to bridge the surgical coloboma with permanent fibrous scar tissue. To investigate this unusual lack of proliferation of the cells of the iris following injury, tissue culture studies of the human iris were undertaken. While embryonic and adult irises of different vertebrates have often been explanted and kept as permanent strains, adult human iris has to our knowledge never been cultivated successfully. Material and Methods Thirty-two segments of human iris were obtained from various surgical procedures, taken