The following preparations were used and the results observed in a series of over 3,500 patients with trachoma at the Missouri Trachoma Hospital during 1941-1951: sulfanilamide, sulfapyridine, sulfathiazole, sulfathiazine, sulfacetamide ("albucid"), sodium sulfacetamide ("albucid" soluble), sulfamylon® (4-amino-2-methyl benzene sulfonamide hydrochloride), diacetylaminoazotoluene (prontosil®), combisul® (a combination of sulfadiazine, sulfamerazine, and sulfathiazole), sulfisoxazole diethanolamine (gantrisin®), penicillin, bacitracin, streptomycin, chloramphenicol (chloromycetin®), aureomycin, and terramycin. Some of the sulfonamide drugs were used in tablet form for internal medication and others in aqueous solution, as drops for local instillation into the conjunctival sac. Both of these methods were usually combined, and an overnight coating of the sulfa ointment was also used. The antibiotics were prepared in fresh, buffered, aqueous solutions daily, from crystalline powders supplied in sterile vials, and used for topical application every two hours. Only surface applications of antibiotics were used, since it was felt that systemic injections of adequate dosage do not