The Mediumship of Ben Jonson
The Mediumship of Ben Jonson is a letter written by Arthur Conan Doyle on 16 march 1927, and published in Psychic Science in april 1927.
The Mediumship of Ben Jonson

Dear Sir,—
Jonson is a very old man now, and it is impossible to say how his mediumship may have changed or his moral fibre deteriorated. I am convinced, at any rate, that he was genuine in that long series which Mr. Yaryan, a professional detective of outstanding ability, undertook with him at Toledo, as narrated in a recent number of PSYCHIC SCIENCE. One cannot read Admiral Moore's accounts without feeling that here also the medium's performance was undoubtedly genuine. I have only sat with him once, and the control was limited, as I state in my "Second American Adventure," by the existence of a door, said to be sealed up into the alcove which was used as a cabinet. I was however, much impressed by what I saw on that occasion, and I have no doubt that I shared the same good fortune as Yaryan and Moore. Any simulation would have entailed the presence of at least half-a-dozen clever personators. There was a good red light in the room. That, however, was three years ago, and I cannot answer for present conditions.
A. CONAN DOYLE.
Windlesham. March 16th, 1927.