Mrs. Baker, still rather distrustful, let herself be led back to her couch. But this time she did not attempt a statuesque pose. She sat bolt upright, turning her head from one to the other of us like a nervous robin. “You haven’t missed anything else, you say,” Tarleton began, “so that it looks as though the thief must have been someone who knew what he was taking. The question is how many of your friends knew about this poison?” “Not one of them,” was the positive answer. “I have never mentioned it to a soul.” “Think,” the doctor persisted courteously. “Remember that Captain Armstrong mentions his discovery of it in his book, _Across Sumatra_. Surely some of your acquaintances must have read the book and talked to you about it?” The little woman began to show signs of misgiving. “I can’t remember,” she confessed. She had shown us both already that memory was not her strong point. The consultant prompted her gently. “The person most likely to be interested in such a thing as a new poison would be a scientist or a medical man.” Mrs. Baker’s eyes sought the floor. “I am positive that my doctor knew nothing about it. Besides, I haven’t seen him for the last six months--not since my brother’s death.” The disclaimer was made in a rather shaken voice, however. “But a lady like you must have some acquaintances in the scientific world,” the examiner insinuated. “I was under the impression that I had heard of you as a patroness of science.” The flattery did its work. Mrs. Baker lifted her head again and repaid it with a gracious smile. “I am interested in science,” she admitted. “When my poor brother was alive I used to give At Homes for him to show his curiosities to people. I have had as many as six Fellows of the Royal Geographical Society at one time before now.” “I felt sure of it. And you see your brother may easily have mentioned this bottle, or shown it, to someone without your knowledge.” The birdlike head wavered. “But I am certain that it hadn’t been taken when he died. I had to make a list of everything he left for probate, and I should have missed it if it hadn’t been there. And I have had no At Homes since.” It struck me that this was said rather unwillingly, under the stress of conscience. Tarleton seemed to think the same. The look he gave to the little woman showed me that he believed she was keeping something back. His next question was a bombshell. “May I ask if you have taken any interest in the science of psycho-analysis?” Mrs. Baker’s collapse was pitiful. If the specialist had suddenly changed into a cobra before her eyes she could not have looked at him with greater terror. “What do you mean, Sir Roderick?” she faltered. Tarleton slowly shook his head.