Intratracheal, intracloacal, and subcutaneous injection of living cultures of the fowl coryza bacillus had no demonstrable effect on the susceptibility of fowl to coryza. Intraperitoneal injection was irregularly followed by a definitely altered susceptibility. Growth of the specific bacillus was inhibited in the nasal tract of approximately 70 per cent of 25 birds which had received an earlier intraperitoneal injection.