First Witch: Round about the cauldron go:
In the poisoned entrails throw.
Toad, that under cold stone
Days and nights has thirty-one
Swelt'red venom sleeping got,
Boil thou first i' th' charmed pot.
All: Double, double, toil and trouble;
Fire burn and cauldron bubble...
...Second Witch: By the pricking of my thumbs,
Something wicked this way comes.
--William Shakespeare, Macbeth IV i