Tissue culture propagated bluetongue virus was partially purified and examined
in an electron microscope with the negative staining technique. Virus particles
either with or without a distinct envelope were observed. In some cases the capsids
appeared to be "empty". The capsid was found to have an average diameter of 60
mµ, while the overall diameter of the enveloped particle was approximately 100 mµ.
Some evidence of an icosahedral shape was presented and the number of capsomeres
was estimated at 92. The capsomeres appear to have a hollow, tubular
nature. The findings have been discussed in relation to some other viruses.