When she turned her focus towards the study of medicine, it was the latest in a lengthy familial interest in the profession: her mother supported Christian Guthrie Wright and Louisa Stevenson in the foundation of the Edinburgh School of Cookery and Domestic Economy (later Queen Margaret University), and been an early campaigner on behalf of the cause of medical education for women.

[6] Chalmers Watson's experience working in Plaistow, where her record consisted of more than 1000 confinements with a mortality rate of just over 1 per 1000,[clarification needed] informed the topic of her MD thesis when she returned to Edinburgh the following year.

[1] On 7 July 1917, the Women's Army Auxiliary Corps (WAAC) was formally instituted; Macready had requested that Chalmers Watson be its first Chief Controller and senior officer some months earlier, in February 1917.

She issued a recruiting pamphlet calling on 'every strong healthy and active woman not employed on work of national importance' to volunteer.

"[1] In a recruiting pamphlet she wrote that "this is the great opportunity for every strong, healthy and active woman not already employed on work of national importance to offer her services to her country.

"[1] Although Chalmers Watson had to resign as Chief Controller of the WAAC in 1918 when one of her sons fell ill after an appendectomy, her efforts had already set a precedent that would be followed – and expanded upon – during the Second World War, laying the foundation for the Auxiliary Territorial Service, which became the Women's Royal Army Corps in 1949.

[5] Chalmers Watson was a noted suffragette, and while her own involvement did not include the militant actions of some of her peers, her support was not passive,[1][9] whilst during the establishment of the WAAC, she had concentrated on equality in improving the levels of pay offered to the women taking over men's jobs.

[16] Later in her life Chalmers Watson put politics aside when working on improving health care in Scotland, with anti-suffragist Kitty Murray, who went on to become a Conservative M.P.

[19] Chalmers Watson was also closely involved in the establishment of the Women's United Services Club in Drumsheugh Gardens, Edinburgh, and at the time of her death in 1936, she was its president.

[2] In The Scotsman's obituary notice, published 8 August 1936, the response to her death was said to be a "stunned reaction" characterised by "the inevitable thought – What are all the women's organisations in Edinburgh going to do without her?

[3] In 1923, Chalmers Watson and her husband inherited the Fenton Barns farm in North Berwick, East Lothian, where they began breeding a herd of tuberculin-tested cattle.

Why not, even should a hospital or a ward be beyond reach, establish one or more beds in her honour—she was on the Board of Management of the Royal Infirmary—or else a bursary or research scholarship for women medical students?

So would her memory be kept green and her indomitable courage be a constant inspiration to many earnest workers who—like me—might have very little chance of ever seeing a bronze plaque in a club hall[21]Three years later, this oversight was to some extent redressed when Chalmers Watson's co-Chief Controller at the WAAC, Dame Helen Gwynne-Vaughan, formally opened a gateway to the Elsie Inglis Memorial Maternity Hospital commemorating Chalmers Watson's life and services to medicine and her country.