The idea of using scented envelopes as a method for the Pseudo-psychometry effect first seems to have been suggested by Roy Walker in his Card Mysteries (George Armstrong, 1933). The principle of scent, applied to a Living and Dead test, was done by Tom Sellers and released 1927, in Tricks That Work, p. 9.

Herbert Milton reported using the principle at that time for a card trick, effect unspecified, reported in a news column the The Magic Wand, Vol. XVI, No. 134, June-Sept. 1927, p. 105.