In 1924, W. Lowenfeld1 made a thorough study of the bacteriologic and histologic characteristics of ulcers of the leg. The results of cultures in fifty-one cases of ulcer of the leg revealed the following organisms: Staphylococcus, 44 cases (Staphylococcus aureus, 20; Staphylococcus albus, 24); Streptococcus, 22 cases; Diplococcus lanceolatus, 3; pseudodiphtheria bacillus, 5; Proteus vulgaris, 17; Pyocyaneus, 8; Bacterium coli, 10; Micrococcus tetragenous, 1; Bacterium mesentericus, 1; sterile, 1. None of these bacteria could be viewed as specific. Staphylococcus and Streptococcus were found alone in the largest percentage of cases (Staphylococcus alone eleven times, and with Streptococcus eighteen times; Streptococcus alone fifteen times and with other bacteria thirteen times). With the reduction of the number of bacteria through treatment, there was progressive healing. Histologic examinations have shown that a number of bacteria become progressively less according to the depth of the tissue examined. The greatest number are present on