Studies on the agent of infectious hepatitis; the disease produced in human volunteers by the agent cultivated in tissue culture or embryonated hen's eggs.

The successful cultivation of the virus of infectious hepatitis in chick embryo tissue culture and in the amniotic cavity of the embryonated hen's egg is supported by a comparison of the disease induced in volunteers by the cultivated virus with hepatitis without jaundice resulting from experimental infection with natural infectious hepatitis virus. Both types of viral preparations produced illnesses in comparable percentages of volunteers (83 and 75 per cent, respectively) after similar average periods of incubation (24.4 and 23.4 days, respectively) and of similar average duration (28.3 and 27.6 days, respectively). The disease could be divided in both groups of patients into a primary stage, followed after a short interval of relative well being by the secondary stage. The illnesses in both instances were characterized by anorexia, nausea, vomiting, enlarged, tender livers and abnormal liver function tests, and frequently temperature elevations. They differed in that jaundice was observed in 31 per cent of the cases resulting from infection with natural virus but not in any patients infected with the cultivated virus.