The consultant was facing me as he spoke, and his keen gray eyes were fixed on me with an expression which might have been merely meant to impress me with the gravity of the situation. But my conscience took the alarm. For the first time a sickening conviction seized me that I was being watched. I told myself that my chief had noticed signs of confusion and dread in my behaviour, and had begun to entertain a suspicion that I knew more about the tragedy than I had chosen to reveal. Now it seemed his suspicion had gone deeper. He was actually asking himself if I had taken advantage of my opportunities as an inmate of his house to search for a more subtle drug than morphia, and had stooped to rob him. And although I knew myself to be innocent of any such action, I trembled at the idea. If the bottle or any of its contents should be missing, how could I possibly hope to exculpate myself? I dared not to open my lips. Tarleton, with something like a sigh, went towards the cabinet in which his drugs were stored, took out his bunch of keys and applied one of them to a small steel safe on an inner shelf. I held my breath as the door swung open. He put in his hand, took out a square glass bottle of the size known to chemists as four-ounce, and held it up to the light. The bottle appeared to be full of a gray powder. The glass stopper was covered with black sealing-wax, and he bent his head over it, minutely scrutinizing the edges of the wax, and the impression of a seal on the flat top. “Thank Heaven!” I echoed the ejaculation in my thoughts as he raised his head and looked round at me with a smile of unmistakable relief. “It is exactly as I left it I sealed it with my own signet ring.” He extended his little finger for me to see. “The seal is intact. If this was the poison used, it wasn’t obtained here.” I had reason to feel satisfied. I knew my chief’s generous nature well enough to feel sure that he would feel remorse for his momentary suspicion of me, and would be disposed to atone for it by shutting his eyes to whatever else might point to my being concerned in the case. In fact he now proceeded to give me a short holiday. “I shan’t want you for the rest of the day, Cassilis, if you want to go out. I think we have done all we can till we hear further from the police. I am now going to think quietly over the problem as it stands.” I was thankful to be released. I had certain pressing business to attend to. But first of all I went to my own room and made a copy of the list of names I had been charged to send to Inspector Charles. And although the paper entrusted to me contained twelve names, the one which I posted to Scotland Yard only contained eleven.