A Letter to a Friend

A Letter to a Friend, by Sir Thomas Browne, the 17th century English philosopher and physician, is a medical treatise of case-histories and witty speculations upon the human condition.

Publication

The Letter was first published as a folio pamphlet in 1690, after having been left out of the 1686 posthumous collection of Browne's complete works. Few copies of this pamphlet are extant; several of those which have survived did so because they were bound as an addition to his complete works. It was then included in his 1712 Poshumous Works printed by Edmund Curll, and a 1716 collection titled Christian Morals edited by John Jeffrey.

Morgellons

Browne's pamphlet is the source of a term Mary Leitao coined in 2001 to describe her son's skin condition. She chose the name "Morgellons disease" based on a skin condition described by Browne in Letter to a Friend, thus:
There is, however, no suggestion that the symptoms described by Browne are linked to the alleged modern cases of Morgellons. In 1935, Charles Ernest Kellett MD FRCP, who lectured in the history of medicine at the University of Newcastle medical school, wrote a detailed criticism of Browne's Morgellons reference.