Mitotic Activity of Wounded Human Epidermis**From the Division of Dermatology, Department of Medicine, University of California School of Medicine, San Francisco, California.This study was supported in part by a grant from the Committee on Research, San Francisco Division, Academic Senate, University of California, and by a United States Public Health Service Student Summer Fellowship.The surgical aspects of this study were carried out at Neumiller Hospital, San Quentin Prison, with the cooperation of Dr. Hermann Gross, Medical Director. Glenn Watson assisted in the study.