That is, we made the hypothesis that Au was (or was closely related to) the etiologic agent of "viral" hepatitis and we immediately set about to test it. Our original publication did not elicit wide acceptance; there had been many previous reports of the identification of the causative agent of hepatitis and our claims were naturally greeted with caution. Indeed, an additional paper on Australia antigen and acute viral hepatitis which extended our findings published in 1967 was initially rejected for publication on the grounds that we were proposing another "candidate virus" and there were already many of these. Confirmation of our findings and the first definitive evidence on the relation of Au to post-transfusion hepatitis came soon from Dr Kazuo Okochi, then at the University of Tokyo.