Аннотация:The effect of contactine-chalones from the lung and liver on cell cohesion and on the incidence of spontaneous tumours was studied in pulmonary alveolar (issue of inbred A mice and in the liver of CBA mice. Ten injections of contactine into two-month-old mice increase for a long time cell cohesion as compared with the duration of the life and decrease incidence of spontaneous tumours in the same tissue from which contactine was isolated