Charles Houston, 96, who pioneered the field of high-altitude medicine, died Sept. 27 at his home in Burlington, Vt. In 1953, Houston led eight climbers almost to the top of the 28,251-foot Himalayan peak of K2. On its icy slopes just 3,000 feet below the summit, Houston and his party stalled after a blizzard set in and raged for two weeks. During the wait for better weather, geologist Art Gilkey developed phlebitis in a leg. Houston, who had begun studying high-altitude physiology, thought it likely that a fatal blood clot would reach his lungs. The healthy members of the team, knowing they faced an almost-impossible task of saving Gilkey, nonetheless wrapped him in his sleeping bag and tent and lowered him down the mountain, inch by inch. But one man slipped, and the team, tied together, fell. Only because the youngest member of the party anchored his ice axe in time did they all avoid certain death. When they reached Gilkey's position, however, he was gone, presumably swept to his death. Houston wrote movingly of Gilkey in "K2: The Savage Mountain" (1954), which has become a classic in mountaineering literature, and he carried guilt over the episode for many years thereafter. As a result, Houston gave up mountaineering and devoted himself to the medical dangers faced by climbers.