M.D., Leyden (1748). Practiced in Kendall and London. Elected physician to the Middlesex Hospital (1750). Admitted licentiate of the College of Physicians (1751). Physician to the Foundling hospital (1754).
Elected Fellow of the Royal Society (1752), and served as secretary of the Royal Society (1760-74).
Upon the establishment of the British Museum, he was appointed under-librarian, or keeper of the manuscript and medal departments (1756). In 1776, he was appointed principal librarian, a position he held until his death.