Viral hepatitis continues to be one of the most important and intriguing unsolved problems in the field of infectious diseases. Although the viral etiology was established by tests on human volunteers almost 25 years ago, the numerous attempts to propagate the virus or viruses responsible for the two clinical and epidemiologic forms of the disease in tissue cultures or in experimental animals have been unsuccessful up to the present time. Of the many reports of presumable success, none has been confirmed, and man is still the only susceptible host. Everything that we know about the properties of the virus, the pathogenesis of the disease and the possibility of prevention by γ-globulin has been learned from carefully controlled studies on human beings.
The two forms of viral hepatitis, so-called infectious hepatitis (IH) and serum hepatitis (SH), present differences in incubation period (15 to 50 days for IH and 50 to 180