-The subcutaneous growth of 2 antigenically distinct syngeneic methylcholanthrene-induced murine fibrosarcomas, designated HI and H7, were significantly augmented by the concomitant administration of E. coli endotoxin (LPS). Amounts as little as 0*02 ,-g i.p. potentiated tumour growth. The weakly antigenic tumour, Hi, was more susceptible to provocation by LPS than the more strongly antigenic H...