In the typical deep trance, the medium may not have clear recall of all the messages conveyed while in an altered state; such people generally work with an assistant. That person selectively wrote down or otherwise recorded the medium's words. Rarely did the assistant record the responding words of the sitter and other attendants. An example of this kind of relationship can be found in the early 20th century collaboration between the trance medium Mrs. Cecil M. Cook of the William T. Stead Memorial Center in Chicago (a religious body incorporated under the statutes of the State of Illinois) and the journalist Lloyd Kenyon Jones. The latter was a non-medium Spiritualist who transcribed Cook's messages in shorthand. He edited them for publication in book and pamphlet form.
In the 1930s Harry Price (director of the National Laboratory of Psychical Research) had investigated the medium Helen Duncan and had her perform a number of test séances. She was suspected of swallowing cheesecloth which was then regurgitated as "ectoplasm". Price had proven through analysis of a sample of ectoplasm produced by Duncan, that it was made of cheesecloth. Helen Duncan would also use a doll made of a painted papier-mâché mask draped in an old sheet which she pretended to her sitters was a spirit. The photographs taken by Thomas Glendenning Hamilton in the 1930s of ectoplasm reveal the substance to be made of tissue paper and magazine cut-outs of people. The famous photograph taken by Hamilton of the medium Mary Ann Marshall depicts tissue paper with a cut out of Arthur Conan Doyle's head from a newspaper. Skeptics have suspected that Hamilton may have been behind the hoax.
^ "Glossary of Key Words Frequently Used in Parapsychology" Archived 2010-12-24 at the Wayback Machine, Parapsychological Association website. "Materialization: A phenomenon of physical mediumship in which living entities or inanimate objects are caused to take form, sometimes from ectoplasm." Retrieved January 24, 2006 "Medium – Definition". Dictionary.com. Retrieved 23 March 2007.