The author discusses the confusion, attributable to misleading references, which long obscured the location of the main portion of the William Beaumont papers. The collection was previously thought to be in the National Library of Medicine, but it is actually housed in the Washington University School of Medicine Library. This has been clarified by the discovery of a series of previously unpublished letters of Sir William Osler, as well as by other newly found materials.
The history of the Washington University School of Medicine Library is reviewed, and the facts relating to the disposition of the Beaumont collection in that library rather than the National Library of Medicine are told. Also considered are some of the problems which the dispersion of documentary source materials creates for the scholar. With the Beaumont papers as a case in point, various locations of such materials are cited, and their contents briefly noted.