Wiktionary
mediumism
n. The actions of a medium (person claiming to contact the dead)
Usage examples of "mediumism".
It seems the doctor who's giving the lecture came up from Whitechapel, was born in Middlesex Street, turned to mediumism and the occult.
At this time a wave of interest in spiritualistic charlatanry, mediumism, Hindoo theosophy, and such matters, much like that of the present day, was flourishing.