A study of the effect of organisms on rabbits' appendixes when intravenously injected showed that this organ in these animals was not always the tissue most seriously attacked, and, furthermore, was never the only organ to exhibit alterations in its structure. The injection of large doses of active cultures produced a widely disseminated infection, with the development of lesions in several different organs. Although the material was selected with a view to demonstrate an elective affinity on the part of the organisms for the appendix, we were unable to determine such an affinity, even though the appendix was affected in a large number of animals. The striking feature of the experiments was the almost uniform regularity with which certain organs were attacked. Lesions were found more frequently in the stomach, lungs, skin and endocardium than in the appendix. The entire gastro-intestinal tract was commonly the seat of hemorrhages and presented