WITH THE advent of each new antibiotic it is necessary to evaluate its usefulness in the treatment of those diseases which have not responded in an entirely satisfactory manner to previous methods of therapy. One such disease is meningitis caused by the bacillus Hemophilus influenzae. This disease, which was successfully combated by a combination of antibacterial serum and sulfonamides in about half the patients treated, was found to respond much better to streptomycin, usually in combination with serum and sulfonamides.1 However, since several studies involving small numbers of patients had indicated that some patients would recover when treated with aureomycin used alone,2 it seemed important to us to determine whether the use of aureomycin alone would be optimal therapy or whether supplemental use of some other therapeutic agents would give better results. Since sulfonamides and streptomycin were the drugs which had been shown previously to have the most