In another paper1 we report the results obtained by the subcutaneous administration of sulfadiazine sodium (the monohydrate sodium salt of 2-sulfanilamidopyrimidine) to rabbits with wounds inoculated with a measured amount of culture of beta Streptococcus haemolyticus of known virulence. This study represents the results of the implantation of sulfadiazine (2-sulfanilamidopyrimidine) into similar wounds at the time of operation. METHOD The method was the same as that previously described. Rabbits weighing 2,200 to 3,800 Gm. were used. With the animal under anesthesia induced by intravenous administration of pentobarbital sodium supplemented by light open drop ether inhalation and by means of aseptic technic, a longitudinal incision of 2 cm. was made posteriorly 1 cm. to the left of the midline and 2 cm. caudad to the lowest rib. The incision was carried down to the sacrospinalis muscle, and with a brass cork borer 1 cm. in diameter, a segment of this