In the preceding paper the author reported that the complement fixation test, by improvement of antigen, could be of some use for the serological diagnosis of hepatitis. In addition to this, the author tried the neutralization test and the “Absättigungsversuch” (Wildführ) with the critique of procedures and of criteria for the judgment of results. As the criteria for the judgment of results, the pathological features of animal liver were used. The results were as follows: 1) Using the sera of convalescents, the neutralization test gave appreciable results, though not acceptable as complete. 2) By the combinative use of neutralization test and modified "Absättigungsversuch", however, it was proved that the isolated virus certainly came from the hepatitis patients and no difference was present among the strains of virus. It was approved that these neutralization test and “Absättigungsversuch” were of some diagnostic significance in the combination with complement fixation test.