after first alienating her from her faithful maid. If she has
written any letters they have been intercepted. Through some
confederate they have engaged a furnished house. Once inside it,
they have made her a prisoner, and they have become possessed of
the valuable jewellery which has been their object from the
first. Already they have begun to sell part of it, which seems
safe enough to them, since they have no reason to think that
anyone is interested in the lady's fate. When she is released
she will, of course, denounce them. Therefore, she must not be
released. But they cannot keep her under lock and key forever.
So murder is their only solution."

"That seems very clear."

"Now we will take another line of reasoning. When you follow two
deparate chains of thought, Watson, you will find some point of
intersection which should approximate to the truth. We will
start now, not from the lady but from the coffin and argue
backward. That incident proves, I fear, beyond all doubt that
the lady is dead. It points also to an orthodox burial with
proper accompaniment of medical certificate and official
sanction. Had the lady been obviously murdered, they would have
buried her in a hole in the back garden. But here all is open
and regular. What does this mean? Surely that they have done
her to death in some way which has deceived the doctor and
simulated a natural end--poisoning, perhaps. And yet how strange
that they should ever let a doctor approach her unless he were a
confederate, which is hardly a credible proposition."

"Could they have forged a medical certificate?"