Through the intravenous inoculation of soil suspensions in the tail vein of mice, Blastomyces dermatitidis was recovered from 10 of 356 samples collected in an endemic area at Augusta, Ga. The infected area at Augusta extends for 1.8 miles in the flood plain of the Savannah River where the soil is a fine alluvial silt. Although collecting was done periodically, positive samples were obtained on only two days, 20 March 1962 and 7 February 1963. Structures from which positive samples were collected include three chicken houses, a rabbit pen, a mule stall, a cattle-loading ramp and an abandoned kitchen. All 10 strains of the fungus isolated are typical of the species and are highly virulent for mice. These isolations support the thesis that B. dermatitidis is a self-sufficient saprophyte, capable of surviving and thriving in nature, and that it infects man only rarely by accident.