to prevent two canoes from smashing against the rocks. The flesh wound he received, however, soon gave him tropical fever that resembled the malaria he had contracted while in Cuba fifteen years before. Because the bullet lodged in his chest from the assassination attempt in 1912 was never removed, his health worsened from the infection. This weakened Roosevelt so greatly that six weeks into the adventure, he had to be attended to day and night by the expedition's physician and his son Kermit. By then, he could not walk because of the infection in his injured leg and an infirmity in the other, which was due to a traffic accident a decade earlier. Roosevelt was riddled with chest pains, fighting a fever that soared to and at times made him delirious, at one point constantly reciting the first two lines of Samuel Taylor Coleridge's poem "Kubla Khan": "In Xanadu did Kubla Khan / A stately pleasure dome decree". Regarding his condition as a threat to the survival of the others, Roosevelt insisted he be left behind to allow the poorly provisioned expedition to proceed as rapidly as it could, preparing to commit suicide with an overdose of morphine. Only an appeal by his son persuaded him to continue. Despite Roosevelt's continued decline and loss of over , Colonel Rondon reduced the pace of the expedition to allow for his commission's mapmaking and other geographical tasks, which required regular stops to fix the expedition's position by sun-based survey. Upon Roosevelt's return to New York, friends and family were startled by his physical appearance and fatigue. Roosevelt wrote, perhaps prophetically, to a friend that the trip had cut his life short by ten years. For the rest of his few remaining years, he would be plagued by flare-ups of malaria and leg inflammations so severe as to require surgery. Before Roosevelt had even completed his sea voyage home, critics raised doubts over his claims of exploring and navigating a completely uncharted river over long. When he had recovered sufficiently, he addressed a standing-room-only convention organized in Washington, D.C., by the National Geographic Society and satisfactorily defended his claims. Final years Roosevelt returned to the United States in May 1914. Though he was outraged by the Wilson Administration's conclusion of a treaty that expressed "sincere regret" for the way in which the United States had acquired the Panama Canal Zone, he was impressed