“Not a bad guess. No; Armstrong discovered a minute fungus that grows in the soil round the root of the upas tree, and apparently nowhere else. The animals that browse on this fungus are overcome by sleep, and die without waking. It contains a soporific poison which acts rather like opium at first, but has a peculiar effect on the skin, which it dries up like parchment. You were the first to draw my attention to the parchment-like appearance of Weathered’s face, you may remember.” I did remember. A burden was lifted from my heart by the recollection. Whatever peril I might stand in from the law, I could assure myself at last that I was not a murderer. The drug I had administered to Violet’s persecutor had contained no grain of any other poison than opium. And now I need not fear that I had given him an overdose of that. He had died, he must have died, from the poison discovered by the explorer of Sumatra. And that meant that he had died by some other hand than mine. The specialist continued his explanation. “You see now why I asked you to make no more remarks on what you saw. Whoever used this poison probably believes that he is the only person who possesses any, or even knows of its existence. Armstrong’s book attracted very little notice. It was badly written, for one thing, and there were no illustrations, a fatal omission in a book of travels nowadays. I don’t think there was a word about this discovery in any of the reviews. Naturally the murderer thinks that he is safe from detection.” “How did you come to hear of the poison?” I ventured to ask. “In the simplest way. Captain Armstrong himself brought me a sample to analyse.” Of course! I could have kicked myself. Tarleton was the one man to whom any such discoverer would be certain to come for an opinion. “He had picked and dried a handful or two of the toadstools, as he called them, but they had crumbled on the voyage home, and what he brought me was dust. I detected the presence of an agent not yet known to science, and I gave it the name of upasine. It seemed to me so dangerous that an unknown poison should be in the hands of anyone but a man like myself, that I asked Armstrong to sell me all he had brought home, and he agreed to do it.” “But in that case--your bottle was untouched?” I objected. “True. It is clear that he deceived me. Either he had parted with some of the poison before coming to me, and didn’t like to admit it, or else he kept some for himself as a curiosity. If it isn’t in his possession, I expect to hear of it in the same quarter as the leopard skin and claws.” CHAPTER XV THE LADY OF THE LEOPARD SKIN I got little more out of my chief during the rest of the journey to town. The gold repeater came into action as soon as we were seated in the train, and I could only wonder what was the problem that was still baffling that keen intelligence.