FOSTER, Isaac, physician, born in Charlestown, Massachusetts, about 1740; died in February 1781. He was graduated at Harvard in 1758, studied medicine in this country and abroad, and settled in Charlestown, where he practiced for several years. He was a delegate to the convention of the County of Middlesex in August 1774, and to the first provincial congress of Massachusetts in October of that year. Dr. Foster was appointed a surgeon in 1775, and was for some months at the head of the military medical department, while General Ward commanded at Cambridge, and before the arrival of General Washington. On 20 April the day after the battle of Concord, by urgent request of General Ward and Dr. Warren, he attended the men who had been wounded, and gave up his private practice, which was very large.

On 18 June the day after the battle of Bunker Hill, he was appointed by the committee of safety to attend those who had been wounded there, and was afterward given the post of surgeon of the state hospital, then just opened. In October he was appointed by General Washington director general pro tempore of the American hospital department. Congress shortly afterward appointed Dr. Morgan to that place, but Dr. Foster was still the oldest surgeon in the hospital. Again; in 1777, General Washington appointed him to take charge of the hospitals in the eastern department. He retired from public life in 1780, being in feeble health, but did not resign his commission. Several men eminent in the medical profession studied with Dr. Foster, among them William Eustis and Josiah Bartlett, the younger.