As a trained archivist myself (I have an MLS specializing in archives, records, and information management), I wholeheartedly agree with Fischer about the central importance of the work of archivists in acquiring, preserving, arranging, describing, and making available historically important documents. The success of The Papers of Abraham Lincoln and of all historical scholarship would be hard to imagine without the excellent work of archivists. I can only concur with the sentiment that their crucial role deserves more public recognition, which I took to be the point of Fischer's article. Nevertheless, as Fischer acknowledges, documents in most repositories are not processed at the item level. Archivists do not look at every piece of paper in their holdings. This is especially true in a repository as large and expansive as the National Archives. No archivist knew that the Leale report was in the Records of the Surgeon General because no item-level processing had taken place. It would be inappropriate to characterize a document known by an archivist as a "discovery," but no archivist knew of this report's existence.
I respectfully disagree with Fischer's definition of a discovery. The title of the article suggests it is impossible for a researcher to make an archival discovery. The Papers of Abraham Lincoln is dedicated to identifying, imaging, and publishing all documents written by or to Abraham Lincoln during his lifetime. We have located a number of documents previously unknown to the repository holding them. These are discoveries, in that they add to the corpus of documents that are known by scholars. Fischer states that "a 19th-century professional knew about the Leale report and decided that, as a part of the Surgeon General's correspondence, it was worth keeping in the nation's collections." There is no evidence of this active decision-making taking place. A clerk in the Surgeon General's office filed the report, as they did all other incoming correspondence. On transfer to the National Archives (after the agency's creation in 1934) an archivist may have deemed the entire "Letters Received" series worth keeping, but it's highly unlikely an appraisal decision was made of any particular document.
Furthermore, by Fischer's logic of only considering the very beginning of the report's existence, absolutely nothing created by anyone in history can be subsequently discovered. The tomb of Tutankhamen was not, by this definition, "discovered" in 1922 because those who built the tomb in the 1300s BC knew it was there. Surely if someone uncovers something unknown in living memory (or in the historiographical record) this counts as a discovery.
Finally, Fischer asserts that "the exciting part about the Leale report is not that it was rescued from a 'dusty archive' (an abhorrent turn of phrase!) but that since it's now catalogued, everyone who wants to find it can." This indicates that Fischer herself believes that, at best, the report was difficult to locate prior to my discovering it (I would go a step further: no one knew it existed, so how to locate it was beside the point). I concur with Fischer that the Leale report -- which was not buried in a "dusty archive" but preserved in the sophisticated facilities at the National Archives -- needed no "rescuing." But until this past May it was unknown to researchers or anyone else.