1) Mice were infected intravenously with sublethal dose of virulent Staphylococci, and the viable number of Staphylococci in the organs were investigated during the course of infection.
2) During first 3-6 hours after the injection, microorganisms were cleared from the circulatory blood by R. E. S. organs, and their viable counts in the kidneys and blood decreased.
After initial clearance stadium, microorganisms in the kidney and bone marrow began to increase with logarithmically constant velocity and the body weight of mice decreased.
3) The maximum number in the kidneys and femur &tibia were 10⁹per gram and 10⁵ per femur& tidia respectively. The tissue defence reaction was activated, and no more increase of orgamisms was observed in these organs.
4) No significant difference were found among various strains derived from human lesions on infectious pattern of liver, kidney, bone marrow and blood.