THE reinforcement and the replacement of anatomic structures in animals and man has presented a problem of increasing importance with newer and more radical surgical techniques. Attempts have been made recently to replace structures with metal, plastic, and glass devices. Although these nonfunctional substances are temporarily satisfactory, they deteriorate after a time, set up a foreignbody reaction, or act as foci of infection. We feel that better results might be obtained if viable host tissues could be used. In addition to the sites where substitutes have been tried, there are many structures in the human body, such as the biliary tract, the urinary bladder, and large defects in the peritoneum, for which there has been no satisfactory means of reinforcement or replacement. With the hope of improving upon present methods, we are attempting to produce viable functional substitutes for anatomic structures by using intestinal segments as pedicle flaps. These intestinal