Personal data
William Butter
Born February, 1726   Died May 23, 1805  
in London
Dr. Butter

Married (1767) to Catherine Douglas, a cousin of James Boswell. Sometime physician at Derby.

According to James P. Warbasse in the article "Doctors of Samuel Johnson and his Court":

"[Dr. Butter] practiced at Derby till he acquired moderate fortune and then moved to London. He was the author of a number of treatises, and be came a licentiate of the Royal College of Physicians."1

Dr Butter was married to the daughter of Sir John Douglas, a first cousin of James Boswell. He is mentioned a few times in the Life of Johnson, and it was in connection with a visit by Johnson and Boswell to Dr Butter that the famous quote "We cannot tell the precise moment when friendship is formed..." was coined.

Life of Johnson (1791)

Unless otherwise noted, the source for a dated quotation of Boswell's is generally the corresponding volume of the Yale Trade Editions of Boswell's journals.