1. Spores of the Bacillus welchii group of bacteria were found on 100 per cent of the uniforms of Belgian soldiers who had come directly from the trenches, and in the meshes of all the samples examined of the new cloth from which the uniforms were made.
2. In fifteen out of twenty fresh war wounds members of this group of bacteria were found. Of the fifteen patients, only three later developed gas gangrene. Once the spores of Bacillus welchii have been carried into a wound the deep-lying lacerated muscle tissue appears to be the most important factor in the onset of gas gangrene.
3. Bacillus welchii is able to grow and produce gas in broth containing up to 40 per cent saccharose. Some strains were able to multiply and produce gas in 50 per cent saccharose broth; but none of those examined were able to grow when the concentration of the sugar reached 60 per cent.
4. The bubbling of pure oxygen through milk or dextrose broth cultures of Bacillus welchii has a definite depressor action on the production of gas. This does not appear to be-due to a reduced number of organisms in the culture.