t are you
going to do, sir?" Professor Brierly looked mutely at Norah. She
shook her head helplessly.

For the next twenty-four hours the group suffered that, which is
hardest to bear under the circumstances, inactivity. Twenty-four
hours after the receipt of the second note there came a third, on
the familiar cheap notepaper. This time it was postmarked Lentone,
Vermont. It read:

_"Professor Brierly was told to go to New York. We will not stand
any fooling. Enclosed is a sample of what we will do. If he does
not start at once more will follow."_

This time the note was addressed to Norah. Wrapped securely there
was a small object in the strong envelope. Professor Brierly took
the small object from her hand. It was a human tooth, a tooth with
dried blood on it. It had the ragged roots characteristic of a
baby tooth, when it comes out.

At this moment McCall stepped into the room. Norah turned to him
impulsively and told him of the letter and the accompanying tooth.

"How horrible!" exclaimed McCall. "Professor, we must--"

"Yes, pretty bad," commented Professor Brierly, "something must be
done, quickly. But, there is, as our friend Hale would say,
something wrong with this picture. This tooth did not come from
Thomas's mouth. It--"

"Not from Tommy's mouth?" repeated Norah.

"No, Mrs. Van Orden, you may be certain of that. The roots of a
child's teeth undergo a certain amount of disintegration before it
is ready to give place to the permanent teeth. We will not go into
the mechanical and biological reasons for this destruction; it is
not important. While this is a deciduous tooth, I mean a baby
tooth, it is not Thomas's tooth. How old is Thomas, Mrs. Van
Orden?"

"He was just four and half years old yesterday."

Professor Brierly nodded his snow white head.

"Exactly, I thought so. No baby's tooth at that age shows the
amount of disintegration that this tooth shows. Depend on it Mrs.
Van Orden, this tooth comes from the mouth of a child of not less
than nine years of age."

The group was staring in wide-eyed astonishment. Norah asked
tremulously.

"You are certain of what you say, Professor, that this is not
Tommy's tooth."

"Depend on it, sis," interrupted Matthews. "Professor Brierly
could not be mistaken in a thing like that. What I want to know is
why--why this?"

There was an air of relief in the old scientist's demeanor. He
still looked grim but he had the appearance of a man who has h