1. Aerobic cultures from twenty-four separate samples of the cortex and marrow of apparently normal human bones are sterile.
2. Aerobic cultures from twenty-four separate samples of the cortex and marrow of bones from ten live and apparently healthy dogs show staphylococcus aureus in eight and four-tenths per cent. and subtilis bacillus in four and two-tenths per cent.
3. Blood culture from these dogs has always shown no growth.
4. Streptococcus has not been cultured from ninety-six separate samples of the cortex and marrow of human and dog bones.
5. The streptococcus and staphylococcus recovered and cultured from the contents and lining f some cases of solitary bone cysts are not ordinarily found in normal human bones. They are likely to be in association with and perhaps the cause of the disease.
6. The bone marrow of apparently healthy dogs may infrequently harbor staphylococcus aureus and subtilis bacillus.