Abstract
1. Ectromelia virus can propagate in cultures of strain L cells.
2. The cytopathogenic effect can be used for the titration of virus.
3. The virus produces two kinds of inclusion bodies in L cells, named “B” and “A” bodies.
4. In this system, the specific complement fixing antigen was detected 5hours, the inclusion bodies appeared 6hours, and the infective virus was found 8hours after infection.