During the past several years there has been a resurgence of interest in the meningococcus and the diseases it produces that sometimes has bordered on the hysterical. Several factors seem to have contributed to this widespread reaction, not the least of which was the demonstration in 1963 (1) that sulfadiazine-resistant strains of Neisseria meningitidis could be isolated with relative frequency from both carriers and patients in the military services. As might have been expected, this led to the finding that sulfadiazine could not be used as an effective prophylactic in populations harboring a significant number of carriers of resistant strains.