The rapid advances in vascular surgery during the past decade were in great part due to the introduction into clinical surgery of vascular replacements. During this period of time, experience and long-term experimental studies1 of preserved homologous tissue revealed a marked degree of thinning and calcific degeneration, and, in some instances, aneurysm formation or even rupture. In peripheral vessels, previous experience with autogenous vein grafts had led some investigators to evaluate autogenous vein grafts in the aorta of animals, with or without external reinforcement2-6 but the results indicated that such replacements would be unsafe in the aorta of human patients. These studies being reported represent an evaluation of another readily available autogenous tissue with significant strength and elasticity, namely, skin. These experiments, begun at Columbia University in 1951, were repeated independently in the surgical laboratories of Baylor University, and the joint findings form the basis for this report.