On Food and Cooking

responses to significant tastes — aversion to
the bitterness typical of alkaloids and cyanide,
attraction to the sweetness of nutritionally
important sugars. And some animals have
developed specific detoxifying enzymes that
enable them to exploit an otherwise toxic
plant. The koala bear can eat eucalyptus
leaves, and monarch butterfly caterpillars
milkweed. Humans invented their own
ingenious detoxifying methods, including
plant selection and breeding and cooking.
Cultivated varieties of such vegetables as
cabbage, lima beans, potatoes, and lettuce are
less toxic than their wild ancestors. And many
toxins can be destroyed by heat or leached
away in boiling water.
A fascinating wrinkle in this story is that
humans actually prize and seek out certain
plant toxins! We’ve managed to learn which
irritating warning signals are relatively
harmless, and have come to enjoy sensations
whose actual purpose is to repel us. Hence our