BRBITSH 205In 72 patients with calcific aortic stenosis treated by "closed " transventricular valvotomy the mortality was 17% and good results were obtained in 44%.In 20 patients with subvalvar stenosis the operative mortality was 200% and initially good results were obtained in 55 %, but deterioration in the follow-up reduced these to 30%.The present position and future prospects of surgical treatment are discussed. Tracing.-The aortas were placed on a wooden board and covered with a large sheet of waterproof tracing material which was completely transparent when wet (Kodatrace). This was pinned firmly to the board, thereby flattening the aortic segment, and the board with its attached paper and aorta was placed in a tray and covered with water. If the thoracic aorta was ballooned and would not readily flatten, a longitudinal midline incision was made in the expanded segment to enable it to be pinned out. The outline of the whole segment, and the boundaries of all the lesions were then traced with a pencil. Four types of plaque were recognized: (1) flat sudanophilicfatty streaks; (2) raised sudanophilic; (3) raised non-sudanophilic-fibrous plaques; (4) complicated-plaques showing ulceration, thrombosis, haemorrhage, or calcification. Different symbols were used on the tracing to denote the four types of plaque.