provided for at a later date, he proceeded at once to take the list of
the bottles and cases, whose contents he was bound to destroy. On opening
the safe, these objects were found as the Instructions led him to
anticipate: the dust lying thick on them vouched for their having been
left undisturbed. The list being completed, the contents of the bottles
and cases were thereupon thrown away by the Professor's own hand.

"On looking next, however, for the medicine-chest, no such thing was to
be discovered in the safe. The laboratory was searched from end to end,
on the chance that some mistake had been made. Still no medicine-chest
was to be found.

"Upon this the Widow Fontaine was questioned. Did she know what had
become of the medicine-chest? She was not even aware that such a thing
existed. Had she been careful to keep the sealed box so safely that no
other person could get at it? Certainly! She had kept it locked in one of
her drawers, and the key in her pocket.

"The lock of the drawer, and the locks of the laboratory door and the
safe, were examined. They showed no sign of having been tampered with.
Persons employed in the University, who were certain to know, were asked
if duplicate keys existed, and all united in answering in the negative.
The medical attendant was examined, and declared that it was physically
impossible for Doctor Fontaine to have left his bed, and visited the
laboratory, between the time of writing his Instructions and the time of
his death.

"While these investigations were proceeding, Doctor Fontaine's senior
assistant obtained leave to examine through a microscope the sealing-wax
left on the box which had contained the keys.