l of you," said young Mr. McIntyre,
rising. "I shall have him put under arrest pending advice from
Washington."

"You, may save yourself the trouble, I think, Tommy," drawled Average
Jones. "Mr. Smith will never be called to account in this world for the
murder--execution of Telfik Bey."

"You saw the marks on my finger-nails," said the foreigner. "That is the
sure sign. I may live twenty-four hours; I may live twice or three times
that period. The poison does its work, once it gets into the blood, and
there is no help. It matters nothing. My ambition is satisfied."

"And it is because of this that you let us find you?" asked Bertram.

"I had a curiosity to know who had so strangely traced my actions."

"But what was the poison?" asked Professor Gehren.

"I think Mr. Jones has more than a suspicion," replied the doomed man,
with a smile. "You will find useful references on yonder shelf, Mr.
Jones."

Moving across to the shelf, Average Jones took down a heavy volume and
ran quickly over the leaves.

"Ah!" he said presently, and not noticing, in his absorption, that the
host had crossed again to the tiroir and was quietly searching in a
compartment, he read aloud:

"Little is known of cyanide of cacodyl, in its action the swiftest
and most deadly of existing poisons. In the '40's, Bunsen, the German
chemist, combined oxide of cacodyl with cyanogen, a radical of prussic
acid, producing cyanide of cacodyl, or diniethyl arsine cyanide. As
both of its components are of the deadliest description, it is extremely
dangerous to make. It can be made only in the open air, and not without
the most extreme precaution known to science. Mr. Lacelles Scott, of
England, nearly lost his life experimenting with it in 1904. A small
fraction of a grain gives off vapor sufficient to kill a human being
instantly."

"Had you known about this stuff, Average?" asked Bertram.

"No, I'd never beard of it. But from its action and from the lettered
cabinet, I judged that--"

"This is all very well," broke in Mr. Assistant Secretary Thomas Colvin
McIntyre, "but I want this man arrested. How can we know that he isn't
shamming and may not escape us, after all?"

"By this," retorted their host. He held aloft a small glass vial,
lead-seated, and staggered weakly to the door.

"Stop him!" said Average Jones sharply.

The door closed on the words. There was a heavy fall without, followed
by the light tinkle of glass.

Average Jones, who