In 1942 Cunningham1 reported on the use of sulfapyridine as a hemostatic agent. He found that after sulfamethylthiazole powder had been instilled into the operative wound after radical external frontal sinusotomy for osteomyelitis of the frontal bone the usual considerable postoperative oozing was absent. This observation led him to experiments on guinea pigs. Circular wounds were made on the backs of the animals, and five to seven days later the scabs were evulsed so that an open granulating and freely oozing surface remained. Powdered sulfapyridine, sulfanilamide, sulfathiazole, sulfamethylthiazole2 and talc were sprayed on with a powder blower. The wounds treated with sulfamethylthiazole and sulfapyridine exhibited an immediate tendency to hemostasis, while the wounds treated with the other powders and with talc and untreated control wounds all oozed for from five to ten minutes. The sulfapyridine powder was also found to be