"Accompanied by the Secretary to the University, as a witness, he opened the laboratory door. Leaving the sale of the objects on the table to be 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.

"The result of this examination, and of the chemical analyses which followed, proved that two different kinds of sealing-wax (both of the same red color, superficially viewed) had been used on the seal of the box—an undermost layer of one kind of wax, and an uppermost layer of another, mingled with the undermost in certain places only. The plain inference followed that the doctor's sealing-wax had been softened by heat so as to allow of the opening of the box, and that new sealing-wax had been afterwards added, and impressed by the Doctor's seal so that the executor might suspect nothing. Here, again, the evidence of the medical attendant (present at the time) proved that Doctor Fontaine had only used one stick of sealing-wax to secure the box. The seal itself was found in the possession of the widow; placed carelessly in the china tray in which she kept her rings after taking them off for the night.

"The affair is still under judicial investigation. I will not trouble you by reporting the further proceedings in detail.

"Of course, Widow Fontaine awaits the result of the investigation with the composure of conscious innocence. Of course, she has not only submitted to an examination of her lodgings, but has insisted on it. Of course, no red sealing-wax and no medicine-chest have been found. Of course, some thief unknown, for some purpose quite inconceivable, got at the box and the seal, between the Doctor's death and the return of the Professor from Munich, and read the Instructions and stole the terrible medicine-chest. Such is the theory adopted by the defense. If you can believe it—then I have written in vain. If, on the other hand, you are the sensible young man I take you to be, follow my advice. Pity poor little Minna as much as you please, but look out for another young lady with an unimpeachable mother; and think yourself lucky to have two such advisers as your excellent father, and Your Unknown Friend."

CHAPTER VIII