John Thomas, born in Marshfield, Massachusetts, in 1725, was a
successful medical practitioner, entering the British army first
as a surgeon, in 1746. He took a prominent part in the French and
Indian War, but at its close devoted himself to his profession.
He was, however, among the first to counsel resistance to British
oppression, and having raised a regiment of volunteers, was appointed
brigadier-general by the Provincial Congress on the 9th of February,
1775, and afterward received the same appointment from the Continental
Congress on the 22d of June of the same year. On the night of the 4th
of March, 1776, with three thousand picked men, he took possession
of Dorchester Heights, commanding Boston, where the British were
intrenched, and before morning had thrown up a formidable line of
earth-works,--an advantage which finally led to the evacuation of the
town by the enemy on the 17th of March. The death of Montgomery at
the storming of Quebec necessitating the appointment of an experienced
officer to command the troops in Canada, this duty was assigned to
Thomas,--Congress having advanced him to the rank of major-general on
the 6th of March, 1776. He promptly repaired to his new post, but while
waiting for promised reinforcements, was attacked by small-pox, from
which he died on the 2d of June, 1776, universally respected and deeply
deplored.