1. Pooled specimens of serum obtained from 3 human volunteers three-fourths through their respective 56, 66, and 70 day incubation periods of homologous serum jaundice produced the disease in 1 out of 4 human volunteers following parenteral inoculation.
2. Serum specimens obtained from these same 3 patients during the acute, pre-icteric phase of their homologous serum jaundice produced the disease in 3 out of 4 human volunteers following parenteral inoculation.
3. These same sera, proven to be infectious by parenteral inoculation, failed to produce disease when ingested by 10 other human volunteers.
4. Pooled specimens of serum obtained in the convalescent phase (28 to 32 days after onset) of these 3 patients failed to produce apparent infection when inoculated parenterally into 5 human volunteers.
5. Pooled specimens of feces of 3 patients obtained in the acute phase of homologous serum jaundice, when virus was proven to be in the serum, were not demonstrably infectious when fed to 6 volunteers.
6. These findings are slightly different from those encountered in a similar study with infectious material from cases of infectious hepatitis.