Dickson believed that without this treatment Drummond would have survived. Dickson was a violent critic of the medical orthodoxy of his day, having been an army surgeon in India where he noticed that bloodletting, which he then applied uncritically to patients with dysentery, malaria, and cholera, usually ended in death. In his Report on the Endemic Cholera of 1829, The Fallacy of the Art of Physic of 1836, and Fallacies of the Faculty of 1839, he accused his fellow practitioners of ignorance, illogicality, and a desire to prolong illnesses in their avidity for the fees with which bloodletting provided them. Among other things he suggested a controlled trial for the efficacy of bleeding in pneumonia.

His own method of treating fever—an emetic, quinine, and cold water splashed on the body—with which he wanted to compare bloodletting was probably less dangerous. But as bloodletting declined as a practice, Dickson received no thanks and even less praise for having pointed out its dangers. He became ever more bitter, criticising in print all the leaders of the profession. His obituary in the Medical Times and Gazette said that he was a man of moderate ability with “a talent for abuse which he exercised to an unlimited extent.” But his worst offence by far was that of having been right.