2 The Weed That Strings the Hangman’s Bag: A Flavia De Luce Mystery by Alan Bradley Page B

teach me the trick. I had practiced in front of a looking glass until my head was splitting, but I could never manage more than a slight lateral googly.
    “God moves in mysterious ways, His wonders to perform,” she had said, when I reported my failure.
    He did indeed. The very thought of Daffy’s words had given me an idea.
    “May I be excused?” I asked, already pushing back my chair. “I forgot to say my prayers this morning. I’d better see to them now.”
    Daffy’s eyes uncrossed and her jaw dropped—I should like to think in admiration.
    As I unlocked the door and walked into my laboratory, the Leitz microscope that had once belonged to Great-Uncle Tar shot me a welcoming gleam of brass. Here, close to the window, I would be able to adjust its reflecting mirror to focus a late beam of sunlight up through the specimen stage to the eyepiece.
    I snipped a lozenge-shaped sample from one of the leaves I had brought from what I now thought of as the Secret Garden in Gibbet Wood, and placed it on a glass slide beneath the lens.
    As I twiddled the focus, with the instrument set at one hundred times magnification, I found almost instantly what I was looking for: the barbed cystoliths that projected like thorns from the leaf’s surface. I flipped the leaf over with a pair of tweezers I had pinched from Feely’s mother-of-pearl vanity set. If I was correct, there would be an even greater number of these clawlike hairs on the underside—and there they were!—shifting in and out of focus beneath the snout of the lens. I sat for a few moments, staring at those stony hairs of calcium carbonate which, I remembered, had first been described by Hugh Algernon Weddell, the great botanist and globe-trotter.
    More for my own amusement than anything, I placed the leaf in a test tube, into which I decanted a few ounces of dilute hydrochloric acid, then corked it and gave it a vigorous shaking. Holding it up to the light, I could see the tiny bubbles of carbon dioxide form and rise to the surface as the acid reacted with the calcium carbonate of the tiny spurs.
    This test was not conclusive, though, since cystoliths were sometimes present in certain nettles, for instance. In order to confirm my findings, I would need to go a little further.
    I was eternally grateful to Uncle Tar who, before his death in 1928, had bought a lifetime subscription to Chemical Abstracts & Transactions, which, perhaps because the editors had never been informed of his death, still arrived faithfully each month on the hall table at Buckshaw.
    Piles of these enticing journals, each issue with a cover the exact blue of a mid-March sky, were now stacked in every corner of my laboratory, and it was among these—in one of the issues from 1941, in fact—that I had found a description of the then newly discovered Duquenois-Levine test. It was my own variation of this procedure that I was about to perform.
    First I would need a small quantity of chloroform. Since I had used the last available bottle for a failed fireworks display on Buckshaw’s south lawn to celebrate Joseph Priestley’s birthday in March, I would first have to manufacture a fresh supply.
    A quick raid below-stairs produced (from Mrs. Mullet’s cleaning cupboard) a tin of chlorine bleaching powder, and from her pantry, a bottle of pure vanilla extract.
    Safely back upstairs in the laboratory, I locked the door and rolled up my sleeves.
    The tin of Bleachitol was, in reality, no more than calcium hypochlorite. Would calcium hypochlorite, I wondered, by any other name smell as sweet? Heated with acetone to a temperature of somewhere between 400 and 500 degrees Fahrenheit—or until the haloform reaction occurs—a quite decent chloroform may afterwards be extracted from the resulting acetate salts by simple distillation. This part of it was, as they say, a piece of cake.
    “Yarooh!” I shouted, as I poured the results into a brown bottle and shoved home the cork.
    Next, I stirred a half