Volumes of evidence about Mrs. Piper have been published by Dr. Hodgson, who unmasked Madame Blavatsky and Eusapia Paladino.[18] He was at first convinced that Mrs. Piper, in her condition of trance, obtains knowledge not otherwise and normally accessible to her.  It was admitted that her familiar spirit guesses, attempts to extract information from the people who sit with her, and tries sophistically to conceal his failures.  Here follow the statements of Professor James of Harvard.

’The most convincing things said about my own immediate household were either very intimate or very trivial.  Unfortunately the former things cannot well be published.  Of the trivial things I have forgotten the greater number, but the following, rarae nantes, may serve as samples of their class.  She said that we had lost recently a rug, and I a waistcoat. (She wrongly accused a person of stealing the rug, which was afterwards found in the house.) She told of my killing a grey-and-white cat with ether, and described how it had “spun round and round” before dying.  She told how my New York aunt had written a letter to my wife, warning her against all mediums, and then went off on a most amusing criticism, full of traits vifs, of the excellent woman’s character.  (Of course, no one but my wife and I knew the existence of the letter in question.) She was strong on the events in our nursery, and gave striking advice during our first visit to her about the way to deal with certain “tantrums” of our second child—­“little Billy-boy,” as she called him, reproducing his nursery name.  She told how the crib creaked at night, how a certain rocking-chair creaked mysteriously, how my wife had heard footsteps on a stair, &c. &c.  Insignificant as these things sound when read, the accumulation of them has an irresistible effect; and I repeat again what I said before, that, taking everything that I know of Mrs. Piper into account, the result is to make me feel as absolutely certain as I am of any personal fact in the world that she knows things in her trances which she cannot possibly have heard in her waking state, and that the definitive philosophy of her trances is yet to be found.  The limitations of her trance information, its discontinuity and fitfulness, and its apparent inability to develop beyond a certain point, although they end by arousing one’s moral and human impatience with the phenomenon, yet are, from a scientific point of view, amongst its most interesting peculiarities, since where there are limits there are conditions, and the discovery of them is always the beginning of an explanation.

’This is all I cam tell you of Mrs. Piper.  I wish it were more “scientific.”  But valcat quantum! it is the best I can do.’

Elsewhere Mr. James writes: 

’Mr. Hodgson and others have made prolonged study of this lady’s trances, and are all convinced that supernormal powers of cognition are displayed therein.  They are, prima facie, due to “spirit control.”  But the conditions are so complex that a dogmatic decision either for or against the hypothesis must as yet be postponed.’[19]