"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.