a scientist who has passed on to join the living dead. He will ask
technical scientific questions that nobody but a scientist can answer
and that the medium can by no possibility even understand when they are
answered. Or suppose he gets a communication from the medium's hand
signed by a great author. The living dead man writes a criticism, let us
say, of some new book and does it in his characteristic style, full of
the power of keen analysis and sound literary judgment. Surely nobody
can believe that the medium is producing such things on her own account.
If she could do so she would not be earning her living as a medium. But
the scientists do not stop there. We often hear the expression
"cross-correspondence." Just what do they mean by that and in what way
does it prove the personal identity of a dead man who is communicating?
The principle may be illustrated by the hotel clerk's method. Sometimes
a guest leaves a sum of money with the clerk, and he wishes to be
perfectly sure of his identity when he returns to claim it. He requests
the guest to put his signature on a card. Then he tears the card in two,
gives him one piece and keeps the other. That gives him a double proof
of identity. When he comes for his money he must first give his name and
then produce the piece of card that fits into the ragged edge of the
piece the clerk has retained, the two together making the whole and
restoring the signature. It's one of the simplest but most satisfactory
proofs possible. Neither piece of that card alone is intelligible. If
one piece should be lost and others should find it nobody could read it
or make anything of it. Nobody could guess the name unless he had the
other piece. He knows only about the part he holds. He may be a thief
and may earnestly desire to use what he has found to defraud, but he is
helpless because he has only one of the two parts it requires to make an
intelligible whole. That is the principle involved in identity by
cross-correspondence. Part of a message is written through one medium
and part through another medium at another time in another place and
neither part presents a complete statement or has coherence until it is
fitted into the other part; and that prevents a medium who is dishonest
from manufacturing a story that may be more or less plausible.

We are by no means wholly dependent upon scientific investigation for
evidence that the dead still live. Hundreds of people are sufficiently
sens