The rate of mitotic division in regenerating epithelium in the dog.

An account is given of the changes which took place in the rate of mitotic division of the epithelial cells, over and around healing unprotected circular full-thickness excised skin wounds in the thoracic and metatarsal regions of the dog. The rate of division increased during the first 24 h and the maximum rate in the epidermis around the wound was reached after two to six days when 4-7 to 6-0 per cent of the cells were dividing. Mitotic figures were seen in the migrating epithelium on the second day. As the mitotic rate in the epidermis around the wound became less the rate in the newly-formed epidermis over the wound increased.