My chief and I looked at each other. There was no need of words to express the idea we had in common. There could be little doubt as to Weathered’s line of action. He had found himself dealing with a credulous weak-minded simpleton, and he had proceeded to use the power of suggestion. He had simply put into the poor woman’s mind the thoughts he pretended to be driving out. The only question that remained was whether he had gone so far as to instigate her to the commission of a crime. “I wrote him letter after letter,” Mrs. Baker continued. “Every time I felt angry with one of the maids I had to let him know. Sometimes he answered the letters, and sometimes he didn’t. When he did write he generally asked me questions about how I was tempted to commit the murder. That was how he found out about the poison.” Even I had seen this coming. Tarleton no doubt had seen it some time before, and worked up to it deliberately; but he let no sign of satisfaction appear. “Did he ever ask you to let him have it?” he asked. The answer surprised me. “No, never. He told me to be very careful never to part with it.” “Ah, I understand. He told you to take the greatest care of it, and you told him exactly where you kept it?” “Yes, yes.” The explorer’s sister gazed at him in admiration. “How did you guess that?” “I think it is quite plain, ma’am. He didn’t want you or anyone else to be in a position to say that he had obtained the poison from you. With the information you gave him he could walk into the house at any time, and take it--secretly.” This was a development I hadn’t foreseen. Was the mystery going to resolve itself into a case of suicide, after all? After failing to put an end to himself by means of opium, had Weathered finally resorted to a more certain drug? But then, in that case, why shouldn’t he have demanded it openly from his deceived patient? Truly the riddle was becoming more insoluble as we advanced. Mrs. Baker was rather indignant at the suggestion that her precautions for the security of the dangerous bottle had not been sufficient; but the consultant brushed aside her objections almost irritably. “Nonsense, my dear woman, that lock of yours could be picked by a clever child of twelve. All that the thief had to do was to come to the house when he knew you were out, give a false name to the servant, and ask to be allowed to wait. As soon as he found himself alone in this room he could help himself to what he wanted, and then remember an engagement, and come away. Very likely the maid who would let him in wouldn’t even trouble to tell you a visitor had called.” The mistress of the house was reluctantly obliged to admit this possibility. Tarleton folded his arms, a sign that the interview was over as far as his interest in it was concerned, but he was good enough to give me a chance of satisfying my curiosity. “What do you say, Cassilis? Do you think we ought to ask Mrs. Baker to tell us anything more?”