Medical Pioneer. A surgeon, his development of colonoscopy has saved countless lives. Raised in the Bronx from age two, he received his undergraduate degree from New York University, earned his M.D. at the University of Maryland, and completed his internship and surgical residency at Manhattan's Bellevue Hospital. Dr. Wolff was to gain much experience during his World War II Army service in Europe then following the conflict was to work for a time at V.A. hospitals in the Bronx and in Butler, Pennsylvania. He was chief of surgery at Manhattan's Beth Israel Medical Center when a 1966 conference in Denmark introduced him to fiberoptic endoscopy, at that point used on the upper gastrointestinal tract. In that time endoscopic examination of the large intestine (colon) was limited to about 10 inches by the thin walls of the organ and by the impossibility of negotiating the first turn with a rigid device. Dr. Wolff and one of his residents, Dr. Hiromi Shinya, set about correcting the situation with Dr. Wolff inventing the flexible scope and Dr. Shinya the snare to remove polyps, then thought to be benign growths but now known to be the origin of virtually all colonic malignancies. The pair started performing their procedures in the late 1960s and along the way perfected the now usual one operator colonoscopy; waiting to publish his findings in the "New England Journal of Medicine" until he had logged 100 cases, Dr. Wolff was to see his efforts establish the standard of care. Colonoscopy was to receive a major publicity boost when it was used to diagnose President Reagan's cancer and was to gradually gain near universal usage. Dr. Wolff lived out his days in Manhattan and died of the effects of advanced age. At his death 1.6 million colonoscopies were performed in the United States annually and, despite the largely preventable nature of the disease, 50,000 Americans continued to die of colon cancer every year.