STUDIES ON A BACTERICIDAL AGENT EXTRACTED FROM A SOIL BACILLUS : III. PREPARATION AND ACTIVITY OF A PROTEIN-FREE FRACTION.

A cell-free extract of cultures of an unidentified soil bacillus, which exerts a bactericidal effect on Gram-positive microorganisms, has been described in previous reports; the first active preparations which were obtained were found to contain a protein precipitable at pH 4.5. It is shown in the present report that the bactericidal agent can be obtained in an active form free of protein. The new purified preparations retain all the activity of the original material, both in vitro and in vivo.