I ought not to have felt so intensely anxious as I watched those bushy eyebrows knitting themselves over a meagre list of names and dates. The dead man’s patients had been numerous, and most of them no doubt had come and gone without the least suspicion of anything irregular in the doctor’s practice, and without compromising themselves by any indiscrete confidences. What evidence could such a book afford against anyone? Still, I was uneasy. My instinct warned me that Tarleton would find some information that he needed in those pages. And my observation told me presently that he had found it. “Listen, Cassilis. Most of these appointments seem to be perfectly innocent and normal. But there are certain names occurring more than once that have numbers attached to them. What do you make of this?--Sir George Castleton, 17; he has been coming once a fortnight. Mrs. Worboise, 21; about once a month. Miss Julia Sebright, 8; she seems to have dropped off. Colonel Gravelinas, 26; h’m. Mrs. Baker, 35; rather more recent than the others. Lady Violet Bredwardine--what is the matter?” I jerked myself round towards the door of the room. “I thought I heard someone outside.” By a stroke of good luck someone was. The door opened as I spoke, and Sarah Neobard appeared with a hat on ready to go out. Tarleton quietly closed the book and placed it in his pocket under her eyes. “I am taking Dr. Weathered’s appointment-book, Miss Neobard. I shall have to make inquiries about some of his patients.” The stately Sarah’s eyes flashed vindictively. “You are welcome to any information I can give you about them, Sir Frank. One of them is at the bottom of this crime, you may be sure.” Tarleton lifted his eyebrows. “We don’t yet know that it is a crime--in that sense,” he said with an air of doubt. “Dr. Weathered seems to have been drugged by someone who wanted to get his keys. But whoever did it may not have meant to give a fatal dose.” I listened anxiously. I was puzzled to understand the specialist’s theory. Did he consider that Weathered had succumbed to a dose that would not have killed a man in ordinary health? And if so, was his death due to some organic weakness, as I had myself suggested when we were viewing the corpse? Or was it possible that Weathered was in the habit of taking the pellets found upon him, after all, and that he had just absorbed such a quantity of the poison into his system that the extra dose proved mortal in consequence? My experience was not enough to enable me to form a decided opinion of my own on either of these alternatives. While these thoughts were passing through my mind Miss Neobard was scrutinizing my companion’s face with suspicion. “You are not saying what you really think, Sir Frank,” she pronounced boldly. “He has been murdered, and you know it, but you are afraid of shocking me by saying so outright. You needn’t mind. I look on this as a judgment, and I have seen it coming.”