h his own.

"What I think," said Mr. Barnes, "is not to the point. My question is
a simple one. Will you reply to it?"

"Well, yes! We did have such a culture tube in the laboratory."

"Did have," said the shrewd detective, quickly. "Then it is not there
now. Where is it?"

"I do not know. I think the Doctor took it away. Of course he used it
in some harmless experiment, or--or--or--or for making slides for the
microscope."

"You mean that you surmise this. All you know is that Doctor Medjora
took the tube out of the laboratory. Am I not right? Now when did that
occur? You saw him take it, did you not?"

Leon stared helplessly at his tormentor for a moment, great beads of
perspiration standing on his brow. Then starting to his feet he
exclaimed:

"I will not answer your questions! I have said too much! You shall not
make me talk any more," and with a mad rush he darted from the room,
and disappeared upstairs.

Mr. Barnes made no effort to arrest his flight. Indeed he sympathized
with the lad, well comprehending the mental torture from which he
suffered. He pondered over the situation awhile, and finally appeared
to have decided upon a plan of action. He took a card from his case,
and wrote upon it these words:

"Mr. Barnes, detective, would like to see Dr. Medjora,
concerning the coincidence of the death of his two wives.
This matter is pressing, and delay useless."

This he placed in an envelope which he took from a desk that stood
open, and then he touched a gong, which summoned a servant.

"Hand this to Dr. Medjora, immediately. I will await a reply here."

Ten minutes elapsed, and then the servant returned, and bidding Mr.
Barnes follow him, led the way to the laboratory. Here Dr. Medjora
received the detective, as though he were a most welcome visitor.

"So, Mr. Barnes," said the Doctor, opening the conversation, "you have
attained your ambition, and are now a full-fledged detective. I have
read something of your achievements, and have watched your progress
with some interest. I congratulate you upon your success."

"Dr. Medjora," said the detective, with much dignity, "the object of
my visit is so serious that I cannot accept flattery. We will proceed
to business, if you please."

"As you choose! Let me see! From your card, I judge that you fancy
that there is some suspicious circumstance about my late wife's death.
You speak of a coincidence which connects hers with that of my first