Adventurer, seems to have been born in Aberdeen about the beginning of the eighteenth century, and to have been a younger son of the Rev. Thomas Blackwell (1660–1728), principal of Marischal College. He may or may not have studied medicine under Boerhaave at Leyden, but about 1730 he was a printer in London, and becoming bankrupt in 1734, was supported in prison by his wife, who published an Herbal (2 vols., fol., 1737–39), with 500 cuts of plants, drawn, engraved and colored by herself, her husband adding their Latin names, with a brief description of each. Next, in 1742, Blackwell turned up in Sweden, where, having cured the king of an illness, he was appointed one of the royal physicians, and undertook the management of a model farm. While still in the full enjoyment of court favor he was charged with being concerned in a plot against the constitution, and after being put to the torture, was beheaded on the 9th of August 1747, protesting his innocence to the last.
