The Distribution of Acid-Fast Bacteria in Soils

Using a technic devised by Söhngen, we have been able to demonstrate the presence of acid-fast bacteria in a hundred samples of soils collected from various parts o f the United States. A technic is described by the use of which many, if not all, of these organisms may be isolated in pure culture. The organisms isolated in pure culture present a diversity of cultural features in many instances resembling those of well known organisms. They have been grouped into three rough groups on the basis of cultural features. By means of cutaneous tests on sensitized or immunized guinea-pigs it has been shown that the organisms of any one of these groups exhibit a closer relationship to each other than to organisms of the other groups.