The need for easily available vascular grafting material is apparent. Several years ago, prior to the development of successful synthetic prostheses, we undertook a study of better and safer methods of aortic homograft preservation than were then in use in this country. Stimulated primarily by enthusiastic experimental1,2 and clinical3-5 reports from Utrecht, Holland, on the use of homografts preserved in acid-buffered formalin, we carried out certain long-term studies in experimental animals to evaluate this technique of preservation. Of particular appeal was the complete sterility and simplicity of storage in formalin as opposed to the relatively elaborate procurement, preparation, and storage precautions essential to nutrient media,6 freezing,7 or freeze-drying8 methods.
Although preservation of vascular grafts by use of acid-buffered formalin is of relatively recent origin, unbuffered formalin preservation was first successfully employed by Guthrie9 in 1908. Conflicting experimental reports of the efficacy of