SummaryStreptomycin in the amounts of 0.4 to 4.0 μ/cc is bactericidal for different strains of P. pestis in 5 days. Advanced experimental bubonic plague in mice is completely cured with 500 μ/3 hours for 3 days, or a total of 120 mg. Between SO to 90% of the mice in a state of septicemic plague may be saved with a total of 1,200 to 1,600 μg. The remarkable bactericidal action of streptomycin is best demonstrated on experimental pneumonic plague; 5 mg of the antibiotic sterilize lungs and lymph nodes within 100 hours after treatment has been instituted. It is recommended that human plague be treated as soon as diagnosed with 2 to 4 g of streptomycin daily depending on the state of infection.