Vance lay back drowsily in his chair, and Markham again took up the interrogation.

“How long did you remain in your room, Miss O’Brien, after you had called Miss Ada?”

“Until the butler came and told me that Doctor Drumm wanted me.”

“And how much later would you say that was?”

“About twenty minutes—maybe a little longer.”

Markham smoked pensively a while.

“Yes,” he commented at length; “it plainly appears that the morphine was somehow added to the bouillon.—You’d better return to Doctor Drumm now, Miss O’Brien. We’ll wait here for him.”

“Hell!” growled Heath, after the nurse had gone up-stairs. “She’s the best woman for this sort of a job that we’ve got. And now she goes and falls down on it.”

“I wouldn’t say she’d fallen down exactly, Sergeant,” dissented Vance, his eyes fixed dreamily on the ceiling. “After all, she only stepped into the hall for a few seconds to summon the young lady to her matutinal broth. And if the morphine hadn’t found its way into the bouillon this morning it would have done so to-morrow, or the day after, or some time in the future. In fact, the propitious gods may actually have favored us this morning as they did the Grecian host before the walls of Troy.”

“They will have favored us,” observed Markham, “if Ada recovers and can tell us who visited her room before she drank the bouillon.”