Physician and philosopher. Married (1752) a daughter of Dr William Oliver.
Although a Doctor of Physic from Leyden University (which was also attended by James Boswell's father Alexander Boswell at roughly the same time), in 1734 he became Professor of moral philosophy at the University of Edinburgh. He was appointed physician-general to the armed forces in the Low Countries in 1744, and in 1752 published Observations on the Diseases of the Army, one of the defining works in modern military medicine, of which he is considered to be the founder. In 1766 he was made a baronet. In 1772 he was elected president of the Royal Society. He died in London on January 18, 1782, and is honoured with a monument in Westminster Abbey.
He was a close friend of Boswell's father, who described him in a letter in 1763 as "the most sincere friend I ever had".1
Dr Pringle is first mentioned in the journals when Boswell dined at his place in London on Sunday, November 21, 1762. Pringle was a friend of Boswell's father but seemed to be somewhat more sympathetic and understanding of James Boswell than his father. Pringle on some occasions served as an intermediary between the two. Boswell thought Pringle often to be in a bad mood.1
Pringle and Boswell met and corresponded infrequently from the early 1760s until Pringle's death in 1782.
The works of John Pringle doesn't seem to have been reprinted for a couple of centuries, but it is possible to find some original copies from the 18th century of Observations on the Diseases of the Army on online used books search engines such as AbeBooks. It is also possible to find a few copies of A Discourse Upon Some Late Improvements of the Means for Preserving the Health of Mariners.
(Be sure not to confuse Sir John Pringle with John R. Pringle who is a present-day biologist, or John J. Pringle, an economist)