Studies were performed on chicken sarcoma of Chiba and Rous strains and undermentioned results wer obtained. (1) Blood picture and serum protein changed regularly according to the development of sarcoma. (2) Temporary interruption of blood circulation by blockade had no effect on chicken bearing sarcoma of both strains. (3) “Toxohormone” was extracted from sarcoma tissue of both strains and perfused fluid was collected through sarcoma tissues of both. strains. (4) Very similarly pharmacological actions were observed between toxohormone and perfusate. (5) The resistance against sarcoma was obtained in chicken by pretreatment of toxohormone. (6) The increasing of resistance by toxohormone pretreatment seems mainly due to the histogenous factor.
