“That is the X in the name of this; it means they haven’t an iota of information on one ingredient, except by its effect; by K, they mean they can halfway guess at the other; it seems to be the masterpiece of an Austrian chemist known as Stenewisc who hides himself most successfully somewhere on the East Side here. If he’d been born in the Borgias’ time, he’d have been Lucretia’s favorite; for his stuff killed Costrelman and Swan and almost killed half a dozen more without giving the slightest warning till the physical seizure came, and without leaving an external trace.” “Poison to kill has to get into one,” Sencort came back, not giving up yet. “If it wasn’t in the food or in the drink, where was it?” “What,” returned Teverson, sticking to the Socratic, “goes into one’s body beside food and drink?” “Air’s all I can think of.” “All I can,” Teverson admitted. “And, with that in mind, I believe I’ll have a look around our directors’ room myself, if you’ll hold, up our meeting for a few minutes.” “Damn foolishness,” acceded Sencort graciously. “Pipes were what I was particularly warned against,” I said to Teverson. “Come along,” he invited me; so I went with him to the fifth floor, passed Weston and Reed on guard outside to see that nobody carted in time bombs since they’d last reported the room clear, and we stepped into the regular, long-tabled, black-walnut panelled mausoleum sort of room which directors picked for their deliberations a generation or so ago. There it was, with two windows to the street and both closed; it was winter, you see, and Sencort wasn’t the only near octogenarian to rally round that walnut. It had electric lights and nothing else but a steam radiator, carpet and chairs and five old etchings on the walls. Everything was clear; nothing was wrong in the drawers or under the tables or chairs or even under the carpet. Reed had carefully tested the radiators and steam pipes. They were absolutely in order. But I kept poking about the room and, behind an etching, I found the capped head of an old gas pipe which evidently brought illuminating gas to the room in the days before electric lighting. It was capped, I say, and looked quite all right, but I happened to put my fingers behind the cap. Then I called Teverson; and he felt, and called Reed. “What do you think of _that_?” he asked. _That_ was a slot--rather a series of slots--cut through the pipe behind the cap on the right wall. You couldn’t see them from the front; you hardly could see them when you pressed cheek to the wall but you could feel them top, bottom and sides of the pipe cut through, leaving just enough metal to hold the cap in place; and freshly cut; for the edges were sharp to your fingers and shining to your eyes. But of course every scrap and shaving of the metal had been cleaned away. The pipe behind the cap back of an etching on the opposite wall was exactly like this. “It was to come that way, I guess,” I said carefully to Teverson.