One of the major problems in vascular surgery is the need for satisfactory blood vessel substitutes. Because of the difficulties in procurement of arterial homografts as well as certain defects in their behavior, and because of the limited usefulness of autografts, search continues for a satisfactory synthetic arterial replacement. This case is being reported because it illustrates dangerous deficiencies in a type of arterial replacement which has seen fairly wide use and which in fact is still occasionally being commented on favorably in the literature.1 Report of Case A 74-year-old white man was admitted to Meadowbrook Hospital on June 13, 1956, with the chief complaint of vague right-sided abdominal pain of 24 hours' duration, becoming increasingly severe and associated with several episodes of emesis. He had been in good health until the present episode. Shortly prior to admission he had taken an enema and collapsed. Examination revealed an alert,