Virological methods (i.e. tissue culture, animal inoculation, etc.) had been used for many years prior to our work to search for hepatitis virus but had not been very productive. Our initial discoveries were based primarily on epidemiologic, clinical, and serological observations. Here, I will try to review the early virology work from our laboratory. Bayer et al., using the isolation techniques initially introduced by Alter and Blumberg, examined isolated Au with the electron microscope. They found particles about 20 nm in diameter which were aggregated by anti-Au antiserum. There were also sausage like particles of the same diameter, but much elongated.