Poirot locked the door on the inside, and proceeded to a minute inspection of the room. He darted from one object to the other with the agility of a grasshopper[67]. I remained by the door, fearing to obliterate any clues. Poirot, however, did not seem grateful to me for my forbearance.

      ‘What have you, my friend?’ he cried, ‘that you remain there like—how do you say it?—ah, yes, the stuck pig?’

      I explained that I was afraid of obliterating any footmarks.

      ‘Footmarks? But what an idea! There has already been practically an army in the room! What footmarks are we likely to find? No, come here and aid me in my search. I will put down my little case until I need it.’

      He did so, on the round table by the window, but it was an ill-advised proceeding; for, the top of it being loose, it tilted up, and precipitated the dispatch case on to the floor.

      ‘En voilà une table![68]’ cried Poirot. ‘Ah, my friend, one may live in a big house and yet have no comfort.’

      After which piece of moralizing, he resumed his search.

      A small purple dispatch case, with a key in the lock, on the writing table, engaged his attention for some time. He took out the key from the lock, and passed it to me to inspect. I saw nothing peculiar, however. It was an ordinary key of the Yale type[69], with a bit of twisted wire through the handle.

      Next, he examined the framework of the door we had broken in, assuring himself that the bolt had really been shot. Then he went to the door opposite leading into Cynthia’s room. That door was also bolted, as I had stated. However, he went to the length of unbolting it, and opening and shutting it several times; this he did with the utmost precaution against making any noise. Suddenly something in the bolt itself seemed to rivet his attention. He examined it carefully, and then, nimbly whipping out a pair of small forceps from his case, he drew out some minute particle which he carefully sealed up in a tiny envelope.

      On the chest of drawers there was a tray with a spirit lamp[70] and a small saucepan on it. A small quantity of a dark fluid remained in the saucepan, and an empty cup and saucer that had been drunk out of stood near it.

      I wondered how I could have been so unobservant as to overlook this. Here was a clue worth having. Poirot delicately dipped his finger into the liquid, and tasted it gingerly. He made a grimace.

      ‘Cocoa—with—I think—rum in it.’

      He passed on to the debris on the floor, where the table by the bed had been overturned. A reading-lamp, some books, matches, a bunch of keys, and the crushed fragments of a coffee cup lay scattered about.

      ‘Ah, this is curious,’ said Poirot.

      ‘I must confess that I see nothing particularly curious about it.’

      ‘You do not? Observe the lamp—the chimney is broken in two places; they lie there as they fell. But see, the coffee cup is absolutely smashed to powder.’

      ‘Well,’ I said wearily. ‘I suppose someone must have stepped on it.’

      ‘Exactly,’ said Poirot, in an odd voice. ‘Someone stepped on it.’

      He rose from his knees, and walked slowly across to the mantelpiece, where he stood abstractedly fingering the ornaments, and straightening them—a trick of his when he was agitated.

      ‘Mon ami,’ he said, turning to me, ‘somebody stepped on that cup, grinding it to powder, and the reason they did so was either because it contained strychnine or—which is far more serious—because it did not contain strychnine!’

      I made no reply. I was bewildered, but I knew that it was no good asking him to explain. In a moment or two he roused himself, and went on with his investigations. He picked up the bunch of keys from the floor, and twirling them round in his fingers finally selected one, very bright and shining, which he tried in the lock of the purple dispatch case. It fitted, and he opened the box, but after a moment’s hesitation, closed and relocked it, and slipped the bunch of keys, as well as the key that had originally stood in the lock, into his own pocket.

      ‘I have no authority to go through these papers. But it should be done—at once!’

      He then made a very careful examination of the drawers of the washstand. Crossing the room to the left-hand window, a round stain, hardly visible on the dark brown carpet, seemed to interest him particularly. He went down on his knees, examining it minutely—even going so far as to smell it.

      Finally, he poured a few drops of the cocoa into a test tube, sealing it up carefully. His next proceeding was to take out a little notebook.

      ‘We have found in this room,’ he said, writing busily, ‘six points of interest. Shall I enumerate them, or will you?’

      ‘Oh, you,’ I replied hastily.

      ‘Very well, then. One, a coffee cup that has been ground into powder; two, a dispatch case with a key in the lock; three, a stain on the floor.’

      ‘That may have been done some time ago,’ I interrupted.

      ‘No, for it is still perceptibly damp and smells of coffee. Four, a fragment of some dark green fabric—only a thread or two, but recognizable.’

      ‘Ah!’ I cried. ‘That was what you sealed up in the envelope.’

      ‘Yes. It may turn out to be a piece of one of Mrs Inglethorp’s own dresses, and quite unimportant. We shall see. Five, this!’ With a dramatic gesture, he pointed to a large splash of candle grease on the floor by the writing table. ‘It must have been done since yesterday, otherwise a good housemaid would have at once removed it with blotting paper[71] and a hot iron. One of my best hats once—but that is not to the point.’

      ‘It was very likely done last night. We were very agitated. Or perhaps Mrs Inglethorp herself dropped her candle.’

      ‘You brought only one candle into the room?’

      ‘Yes. Lawrence Cavendish was carrying it. But he was very upset. He seemed to see something over here’—I indicated the mantelpiece—‘that absolutely paralysed him.’

      ‘That is interesting,’ said Poirot quickly. ‘Yes, it is suggestive’—his eye sweeping the whole length of the wall— ‘But it was not his candle that made this great patch, for you perceive that this is white grease; whereas Monsieur Lawrence’s candle, which is still on the dressing table, is pink. On the other