Over the next two years she moved where the need took her: field hospitals near Fredericksburg in 1862, the same period that Walt Whitman and Clara Barton were working in Washington-area hospitals, and later to Chattanooga following the Battle of Chickamauga. She was doing physician’s work without physician’s status, treating the sick and wounded of an army that would not formally acknowledge her as one of its surgeons.
She also, at some point in this period, began gathering information. In September 1862 she wrote to the War Department requesting employment as a spy. The request was declined. The nature and extent of any intelligence activity she actually engaged in — whether she systematically gathered Confederate information during her crossings of battle lines, or whether the later claims about her intelligence work were retrospective elaborations — is a point where historians note the limits of the documentary evidence.
## The Commission: Contract Surgeon in the Army of the Cumberland
In September 1863 — more than two years after she first offered her services — Walker received a formal appointment: “Contract Acting Assistant Surgeon (civilian)” with the Army of the Cumberland.
The title requires parsing. “Contract” meant she was a civilian contractor, not a commissioned officer in the United States Army. The distinction was legally significant and practically important. She could not hold rank, could not command, could not expect the protections and privileges that commissioned status provided. She was a hired physician, employed under contract for the specific duration of the arrangement, subject to discharge at the Army’s discretion.