PNEUMOCOCCIC meningitis is well known as one of the most serious forms of bacterial meningitis. Before the sulfonamides were used pneumococcic meningitis was almost always fatal. With the advent of penicillin an era of more successful therapy was started. Originally it was established that when small systemic doses of penicillin were given the result could be greatly improved by administering the antibiotic intrathecally. It was later shown1 that the administration of large doses of penicillin systemically gave still better results and that intrathecal penicillin therapy was unnecessary when this regimen was employed. In spite of these advances, however, approximately one of three persons with pneumococcic meningitis still died, as shown on analysis of series of unselected cases. Consequently, when aureomycin became available and was shown to be effective in therapy of isolated cases of pneumococcic meningitis, we decided to test its efficacy by treating alternate patients with either penicillin