Rankine Dawson, born likely in 1863, was the next to the youngest of the children of John William Dawson and Margaret Mercer Dawson, born after George, Anna, and William Bell. He graduated from McGill College, having been a member of the first McGill hockey team that played and won (2 to 1) its first match 31 January 1877. The summer of 1878 he helped his brother George with a survey of the Queen Charlotte Islands. He graduated from McGill Medical School in 1882 having already been admitted to the College of Physicians and Surgeons in 1881. He began his career as a medical officer for Canadian Pacific in Manitoba, then went to London for further training and served as a surgeon on the ocean liners of the P & O Company for 4 years. In 1896, he married Gloranna M. Coats, a wedding which his parents travelled to England to attend, and they had one child, Margaret Rita.

They moved from London back to Montreal but soon returned to London where Gloranna left him. This was probably due to his unstable temperament and severe bouts of depression, a chronic problem for him which had earned him the reputation among family members of being impractical and rebellious. When he visited Montreal, he was regularly given a special room to himself and his mother may have used the passageway that had been constructed between the older Dawsons’ residence and the Harringtons’ (her daughter’s family) next door to retreat from her difficult son’s company.

He was not on close terms with his father, who was dubious about his worldliness and material concerns. However, in the last year of Sir William’s life, 1899, Rankine visited and seems to have promised to help with the publication of his father’s autobiography, which the latter wished to be published soon after his death with a minimum of editing. This initiated a family feud after the patriarch died. The oldest son, George, who had collaborated with his father and was himself a geologist, claimed that his father had written that the manuscript would be turned over to him, and that Rankine would help him with it, but Rankine maintained that he himself had been entrusted with the publication. Rankine went ahead and published it in 1900 in London against the wishes of his siblings, George and Anna, who had hoped to edit the manuscript to better show their father’s accomplishments. There followed a long bitter estrangement and Rankine died in a London nursing home in 1913.