The Physical Phenomena of Mysticism by Herbert Thurston is the result of the author’s tireless study of a wide range of psychic phenomena, including, levitation, stigmata, telekinesis, luminous phenomena, inedia (living without food), and more. The book delves into the phenomena attributed to the likes of, the Catholic stigmatic, Therese Neumann, St. Francis of Assisi, and includes the fascinating story of Mollie Fancher, who it was alleged, following a life threatening accident, could see without her eyes, took little or no food for 14 years, traveled out of body, and demonstrated clairvoyant abilities.

Thurston was a Catholic priest, a member of the Jesuit order, and a historian. He wrote extensively on Catholic mysticism and psychic phenomena. He was a member of the Society for Psychical Research, and was widely read on the subject. 

Given that he was a practicing Catholic, it is unlikely that he attended séances, and therefore his opinion on spirit communication, clairvoyance, and mediumship in general, may not come from personal experience. That said; he comes across as an honest skeptic (rather than a debunker) with some empathy for his subjects.
Explaining his position he says,

The role of Devil’s Advocate is a thankless one and does not make for popularity, Indeed, I may confess that, when writing somewhat in the character of a doubting Thomas, I have felt at times, in spite of good intentions, that I was even playing a mean and an unworthy part.

“Why, I have asked myself, should a skeptical line of argument be put forward which may possibly trouble the simple faith of many good people much nearer and dearer to God than I can ever hope to be? And yet in these days of widespread education, universal questioning and free discussion, a premature and ill-grounded credulity cannot in the long run be of advantage to the Church. The Christian has to be able to justify his beliefs, and adequate equipment for an encounter with rationalists or agnostics requires some previous study both of the position, which it is intended to take up and of the form of attack to which that position may be exposed.”

The Physical Phenomena of Mysticism is essential reading for those interested in Catholic mysticism, and physical and psychic phenomena often attributed to miracles.

Fr. Herbert Henry Charles Thurston, S.J. (15 November 1856 — 3 November 1939) was an English priest of the Roman Catholic Church, a member of the Jesuit order, and a prolific scholar on liturgical, literary, historical, and spiritual matters.

Thurston wrote more than 150 articles for the Catholic Encyclopedia (1907-1914), and published nearly 800 articles in magazines and scholarly journals, as well a dozen books. He also re-edited Alban Butler’s Lives of the Saints (1926-1938).

He was a close friend of the Modernist theologian George Tyrrell.

Many of Thurston’s articles show a skeptical attitude towards popular legends about the lives of the saints and about holy relics. On the other hand, his treatment of spiritualism and the paranormal was regarded as “too sympathetic” by some of his fellow Catholics.

Source: http://en.wikipedia.org/wiki/Herbert_Thurston