1. The etiology of osteitis that is characterized by a fibroblast and giant-cell proliferation with bone destruction and new bone formation has been discussed.
2. A case was reported in which a strain of green-producing streptococcus grew in cultures of a lesion in the neck of the astragalus, which presented a microscopic picture similar to that of localized osteitis fibrosa without cyst formation. Clinically and bacteriologically it was a lowgrade pyogenic infection and has been classed as streptococcus viridans osteomyelitis.
3. A second case, which was clinically and pathologically similar to the first, except for bone proliferation, but in which the cultures were negative, was also reported.
4. That trauma may be a factor in localizing the infection is again suggested by these cases, but the opinion is expressed that reaction to trauma and hemorrhage could not alone account for the cortical absorption and the extensive new bone formation noted in Case 2.