Abstract: | A study was made of the recurrent growth of ascite hepatoma 22A, occurring at transplantation of 11-12-day old tumours to new hosts. The mitotic activity of the hepatoma was found to increase by 3 to 4 times (12-15 hours after inoculation). This increased cell proliferation is due mainly to a sharp shortening of all the periods of mitotic cycle. During the recurrent growth, the resting R1 cells resume their mitotic cycle. No resumption of the mitotic cycle by the resting R2 cells was observed |