1 From the Department of the History of Science (D.S.J.) and the Department of Anthropology (J.P.G.), Faculty of Arts and Sciences, Harvard University, and the Harvard University Native American Program (J.P.G.), Cambridge, the Department of Global Health and Social Medicine, Harvard Medical School (D.S.J., M.A., J.P.G.), and the Department of Surgery, Massachusetts General Hospital (M.A.), Boston - all in Massachusetts; and the Department of Statistics, University of Oxford, Oxford, United Kingdom (M.A.).