In 1902, Scarlett traveled to Norvalspont, Cape Colony to serve, by government appointment, in the concentration camp as part of the Boer War.

[4] Scarlett then moved to Bloemfontein, where she was part of a six-member committee appointed by the British Minister of War to investigate conditions in the concentration camps.

Other members of the committee included Millicent Fawcett and Jane Elizabeth Waterston.

In 1915 Scarlett worked for the Canadian Red Cross teaching first aid and home nursing, as well as organising the first Women's Volunteer Reserve Corps of Canada[6] and becoming the first woman doctor at the Royal Columbian Hospital.

[7] In August 1915, Scarlett traveled to Serbia to distribute medical supplies and visited British prisoner of war camps in Germany.