Abstract
The development of the Marchal body regularly followed the appearance of mature ectromelia viruses within the same cytoplasm. Isolated Marchal bodies in high purity were comprised mainly of protein, the antigenicity of which was quite different from those of NP antigen, soluble antigen or hemagglutinin. Physicochemical analysis revealed that the protein became soluble at pH 11.5 and reprecipitated at its isoelectric point of pH 5.2. There was no significant difference in these properties between Hampstead and Ishibashi strains. Considerable variations with respect to plaque size were found between the two strains.
