[2] He was subsequently admitted a fellow of the College of Physicians, and went into practice in London, but was compelled by bad health to move to the country.
He devoted his attention particularly to the treatment of insanity, and was one of the physicians called in to see George III when he first showed symptoms of mental aberration.
He asserted that the addition of an ounce and a half of muriatic acid to a tun of water, will prevent its putrefaction, and preserve it sweet for any length of time.
An authentic Account of the Part taken by the late Earl Chatham in a Transaction which passed in the beginning of the year 1778 is no longer attributed to Addington.
Henry Addington, 1st Viscount Sidmouth, Prime Minister of the United Kingdom from 1801 to 1804, was their eldest son.