[Sarcomas in syrian hamster, induced by an oncorna virus and cellfree transmissible (author's transl)]

1. Application of hamster papova virus to newborns of Syrian hamster has produced some s.c. sarcomas after a 5 to 6 month latency period, by virtue of the strong inducer effect of this papova virus to endogenous (latent) oncorna viruses. 2. Cellfree filtrates from a polymorphorus-cell sarcoma produced in this way, when applied to newborn hamsters of the spontaneously tumour-free hamster line HaP, again lead to sarcoma formation after a latency period of 3--8 months in about 20% of the animals; the same holds for cellfree filtrates of these cellfree induced sarcomas and their transplantation generations. 3. In these tumours C-type oncorna viruses, but no papova virus, could be demonstrated regularly. 4. The hamster specificity of this sarcoma virus is suggested by the complete absence of a tumorigenic effect of the cellfree filtrates from these hamster sarcomas in mice and rats. The preferential induction of hamster sarcomas by sarcoma filtrates, in conjunction with the fact that filtrates from hamster leukoses, indicates a certain difference between hamster leukemia and hamster sarcoma viruses.