Infectious diseases often appear in epidemic proportions under wartime conditions when it becomes necessary to gather large bodies of troops into crowded quarters. Such conditions are particularly favorable to the spread of the air borne infectious diseases of the respiratory tract. While experimental work with aerosols apparently offers promising prospects for controlling droplet infections, effective technics have not as yet been perfected for employing these substances on a large scale. Several recent reports1 have appeared, on the other hand, showing that small doses of sulfanilamide, given over prolonged periods, will prevent rheumatic subjects from having hemolytic streptococcus infections of the respiratory tract and thereby save them from recurrences of rheumatic fever. In addition, reports have appeared indicating that the sulfonamide compounds have been used effectively to protect scarlet fever contacts2 and prevent meningococcic,3 gonococcic and chancroidal infections.4 It therefore seemed probable that the sulfonamide compounds might