Biography
M.D.. Probably the Morris Coulthard who served as Mayor of Carlisle several times between 1771 and 1796.
A Morris Coulthard, son to Jacob Coulthard (1708-1782), was christened in September, 1731, and died in 1797.
Life with Boswell
Boswell met Morris Coulthard on October 11, 1762, at Springkell, describing him as "an apothecary, a true-looking Englishman with a round-cut head and leather breeches, a jolly dog who sung us a song that the boy sings who sweeps Drury-Lane stage before the chandles are lighted..." Later on in the same entry Boswell described him as my friend Dr. Coulthard.
In 1788 Boswell was elected Recorder of Carlisle during one of Coulthard's tenures as mayor. He resigned the Recordership in 1790.