1. Closed intestinal loops in which bacteria are first removed are compatible with life.
2. Closed intestinal loops in which bacteria are present but in which tissue necrosis is prevented, are compatible with life.
3. Closed aseptic intestinal loops in which the blood supply is completely occluded are compatible with life.
4. The normal secretions and bacterial products of the duodenum and jejunum are not sufficiently toxic to produce any symptoms when allowed to drain into the abdominal cavity.
5. Our results do not support the theory of Draper of a normal toxic secretion of the duodenal mucosa, neutralized by the jejunal mucosa, or the perverted secretion theory of Whipple.
6. Bacterial activity plus necrotic tissue, or the absorption of toxic products resulting from the action of putrefactive bacteria on necrotic tissue is the important factor in the rapid death in simple closed intestinal loops.