Abstract
Three hundred and thirty mice of three strains (BALB/c, C57BL/6, CB6F) received either intrapetitoneal saline Injection of equal volumes of polystyrene microspheres at control state, 1% cross-linked, and 10% cross-linked at 8 Mrads/hr or 80 Mrads/hr gamma radiation, respectively. After 14 months, only one animal (C57BL/6, 1% cross-linked polymer) developed an intraperitoneal lymphosar-coma, while three control animals developed similar tumors, and two developed suspicious atypical lympho-proliferative lesions.