“Upon getting my signal, which you will receive at an opportune moment when she is alone, you must immediately join Mrs. Mortimer Thurlow, at the same time stealthily opening the box and removing the handkerchief.”
“And then?”
“Give it to her at once, without a moment’s delay, and remark she dropped it,” said Graff. “She will infer that it is her own. If not, she will at least raise it toward her face to examine it. Step back a little, meantime, covering your nostrils, that you may inhale no appreciable quantity of that with which the handkerchief is impregnated.”
“What’s the stuff?” growled Dorson, brows knitting.
“Do not be curious.” Professor Graff spoke with a frown. “I have confederates, but to none do I confide my secrets. Take my instructions—and obey them.”
“Well, what more?”
“Watch the woman,” Graff continued. “Only her eyes will change perceptibly. A fixed expression will immediately appear, and her pupils will contract to mere pin points. Take her arm, then, and lead her out through the nearest French window.”
“Suppose she refuses to go, or——”
“She will not refuse or do anything else,” Graff interrupted. “She will go willingly and without a word or a subsequent recollection of what occurs. Place her in the nearest chair on the balcony. Get the handkerchief and return it to the box, then hasten to the ballroom and go after a glass of water. You can afterward assert that she sent you for it and said she felt faint. She will admit it, for she will remember nothing and cannot consistently deny it.”
“But the pearls?” Dorson questioned, eyes glowing. “What of the rope of pearls?”