Surface culture methods of isolating bacteria are generally preferable, not only from the standpoint of simplicity, but also because surface colonies frequently have so distinctive a morphology as to lead to their immediate identification. With the present day methods, however, it is frequently almost impossible to isolate organisms from tenacious masses or from deposits such as tartar. This is often the case from the standpoint of anaerobic bacteriology. Heretofore it has been considered almost impossible to secure pure cultures of anaerobes by other than single cell isolation methods, but that such is not the case has been amply shown by the use of the method to be described. One of the chief purposes of any isolation method should be to effect a thorough and complete separation of the bacteria in the inoculum, while still maintaining to the greatest possible degree the symbiotic relationship of the various organisms. Failure to achieve this result explains many of the unsuccessful attempts to isolate certain of the more fastidious organisms from badly contaminated material. Several serious obstacles to a thorough separation of bacteria exist in present methods of inoculation, chief of which is the light pressure of application of the needle or rod to the surface of the medium, which is necessary in order to prevent cutting the medium, together with the ziz-zag motion of streaking which is so commonly employed. By such a movement of the needle, clumps of bacteria are removed more frequently than individual organisms, especially in those portions of the plate in which the directions of the motion of the needle or rod is reversed. As a result of this few properly streaked plates are secured, with a consequent increased difficulty in the isolation of the bacteria. In addition to these objections it is often very difficult to streak all of the surface of the medium due to the contour of the petri dish, with a consequent decrease in the length of the line of inoculation, and in the degree of separation afforded. Furthermore, due to the