"Sibella's all right. I took her to the Trinity Hospital in Yonkers. A slight concussion—Ada had struck her with a box-wrench which was always kept under the front seat. She'll be out in a few days. I registered her at the hospital as Mrs. Von Blon, and then phoned her husband. I caught him at home, and he hurried out. He's with her now. Incidentally, the reason we didn't reach him at Mrs. Riglander's is because he stopped at the office for his medicine-case. That delay saved Sibella's life. Otherwise, I doubt if we'd have reached her before Ada had run her over the precipice in the machine."
He drew deeply on his cigarette for a moment. Then he lifted his eyebrows to Markham.
"Cyanide of potassium?"
Markham gave a slight start.
"Yes—or so the doctor thinks. There was a bitter-almond odor on her lips." He shot his head forward angrily. "But if you knew"
"Oh, I wouldn't have stopped it in any case," interrupted Vance. "I discharged my wholly mythical duty to the State when I warned the Sergeant. However, I didn't know at the time. Von Blon just gave me the information. When I told him what had happened I asked him if he had ever lost any other poisons—you see, I couldn't imagine any one planning so devilish and hazardous an exploit as the Greene murders without preparing for the eventuality of failure. He told me he'd missed a tablet of cyanide from his dark-room about three months ago. And when I jogged his memory he recalled that Ada had been poking round there and asking questions a few days before. The one cyanide tab-
