Even such a brief foray into chemistry teaches that anything, in a large enough amount, can kill. Life-giving water itself is lethal if you gulp down too many gallons. As toxicologists say, the dose makes the poison. But poison by water doesn’t unnerve us. The real scare comes from those elements and compounds whose toxicity is measured in drips and drops. Luckily for us, and other life on Earth, such materials are rare. But somehow we’ve managed to find or create many of them. We use them pragmatically, and for good—our medicine relies on countless toxic compounds—and in deliberate evil.
