100827
Scope It is intended to be an actual for would-be mediums , containing doctrine and practices that one must master in order to become a medium , an elementary course on theories and basic methods to assess the new light that had never been tried by rational inquiry before : the interaction of the physical and spiritual worlds .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None