I watch my fingers run along the front of the killing fluids, clearing a clean line across the names, a ball of dust gathering in front. The strangest thing of all is that for the first time in my life, I feel more like my true self than ever before.
Clive used to say that to be a successful moth hunter you need not be a specialist, but many specialists: a biologist, a botanist, a chemist, an ecologist, a meteorologist, an expeditionist—and well versed in Latin.
Moths can be extraordinarily fussy. Not only are they particular about which plants they feed from but also the specific habitat in which those plants grow. So, when hunting a moth, you must first uncover the correct plant in the correct habitat and for that you’ll need a good knowledge of the less glamorous corners of the country—for example, where ragwort grows in a low, dry and sheltered dell. The Dingy Mocha, which has been found only twice in Dorset, lives solely on sallow in low wetland, so you’d need to know the boggiest parts of Abbotsbury Heath where sallow scrub abounds, or some badly managed farmland in the wettest parts of the Blackmore Vale. If a couple of Vale farmers decided to clear their scrubland, one of those Dingy Mocha habitats would be wiped out forever.
Once you’ve identified where to find it, you need to get to know the moth well enough to use its own habits to trap it. Should you treacle it, use a light trap or a pheromone lure? Each method has to be adjusted for each species—when they might be on the wing, what recipes for sugaring, which type of light trap and even the intensity of lightbulb to use within it.
Finally, once the moth is caught, you must decide how best to kill it, and for that you need to be a chemist.
Moths, you’ll find, are tenacious of life. You can squeeze their bodies, prick them with pins, even cut off their heads and they’ll live. You can dip a pin in nitric, prussic or oxalic acid, all deadly, stick it into their bodies and, unless you’re very accurate with the concentration, it might not finish them. Each poison has its disadvantages—the rigor mortis of cyanide, the discoloring of ammonia, the stiffening of wings with carbon tetrachloride—so each case must be considered individually.
Tetrachloride is a clean, quick poison but, as I’ve said, it can stiffen the wings, so tetrafluoride is sometimes preferable but makes more mess and tends to alter the colors unless you can preserve them first. Chloroform is a useful poison and especially easy to take into the field, but use too little and it’ll only anesthetize, and too much makes the bodies too stiff. Oxalic acid and potassium cyanide are both deadly and a good choice when dealing with the larger moths. They can be stabbed directly into the belly or dropped into the killing bottle on blotting paper although, again, too much and the bodies will stiffen. Rigor mortis has always been the bane of the setter, as then the specimen has to be relaxed with many days of steaming and softening agents. Often I find a cocktail works best: for a good clean killing, I might stupefy with chloroform first, then stab them with oil of tobacco or oxalic acid. Undoubtedly ammonia is the most suitable for a mass extermination but, like cyanide, it discolors the greens. Ether, chloroform and formic acid will all sedate or kill quite suitably in the field, and crushed laurel leaves, which produce the deadly prussic acid, won’t stiffen the bodies so much although the leaves can’t be collected in damp or dewy weather in case of mildew. In which case prussic acid can also be made by adding a few drops of potassium cyanide to tartaric acid, with a suitable catalyst.
Once you decide on the best poison for the termination, you must then work out the correct concentration. For instance, I know that five milligrams of cetratranic acid dropped into a bell jar with a single moth will take about three seconds to stun it. I know that seven milligrams will anesthetize it and ten is enough to kill it, providing the moth does not weigh more than 3.5 grams. I also know that to kill fifty moths you need five times the concentration or volume of killing fluid, but to kill seven thousand you’d need only two hundred times the concentration. I know that potassium chloride could never kill a larger moth and potassium sulphide would only ever be strong enough to anesthetize it. I know that cyanide kills anything. But what I don’t know right now is the precise amount I will need to kill Vivien.
Monday
Chapter 20
About Monday
7:07 a.m. (by my digital bedside clock)
I must tell you something. When I woke up just a few moments ago I had the most alarming sensation. It was a feeling of instant alertness. Usually my mind lags vaguely behind my brain when it wakes, like the cranking up of an old lethargic engine, taking several seconds to gain full speed. But this morning I know something’s up, because when my eyes opened my mind opened too, eager as a young person’s, with the immediacy of a lightbulb once you’ve flicked the switch. It’s as if my body has sensed something before my brain has had a chance to work it out.
Then, with a bolt of understanding, it strikes me: My little sister, Vivien, is dead.
Dead right here in this house, fifteen yards away in her room in the east wing, along the landing and left through the glass-paned double doors. I feel a sick surge of dread rising from the core of my stomach, spreading menace throughout my frail body. Pricking it coldly. Smothering all my usual morning aches.
Let me think now: I heard her during the night at five to one, when she got up to make her usual cup of tea, but I didn’t hear her again, as I have done every other night she’s been here, going to the lavatory at five, and I haven’t yet heard her this morning going down to get her morning tea, even though it’s now well past seven. Every other morning she’s been like clockwork, straight down to the kitchen at seven on the dot.
I’m still in bed with the blankets pulled up to my chin and my hands locked by my sides. I haven’t moved a muscle since I woke. I don’t dare, for fear that somehow it might upset the delicate balance of life and death that has threatened the house this morning. If I strain my eyes to the right, I can just about see my bedside clock. It makes me feel safer, knowing that it’s there, looking after the time for me.
I think I should tell you there’s a much more substantial reason for my knowing that she’s dead than not having heard her this morning. Did I tell you last night, when I found the poisons upstairs in the laboratory, that I took down a tin of potassium cyanide powder from the very top shelf? I secreted it up the left sleeve of my dressing gown (pinching the cuff around the bottom so it wouldn’t fall out) and took it downstairs to the kitchen. I put half a teaspoonful in her milk in the fridge, then hid the tin behind the bottles in the drinks cabinet in the library. And you know how she likes to take her tea milky.
But, of course, the problem is that I can’t be absolutely, one hundred percent sure she’s dead, unless I go and check on her. What if she’s not dead? What if she’s just half dead? (You can never be sure of getting the correct concentration per pound of body mass.) I can’t have her being found half dead; she’ll be prodded and probed until they find out she’s been poisoned. I can’t think why it didn’t occur to me before—that I’ll have to actually go and check on her. I can’t possibly do that. It’s not within my boundary. I’ve not been in that part of the house for forty-seven years. I wouldn’t feel safe.