ACT IV. SCENE I. A cavern. In the middle, a boiling cauldron. Thunder. Enter the three Witches. FIRST WITCH. Thrice the brinded cat hath mew'd. SECOND WITCH. Thrice and once the hedge-pig whined. THIRD WITCH. Harpier cries, "'Tis time, 'tis time." FIRST WITCH. Round about the cauldron go; In the poison'd entrails throw. Toad, that under cold stone Days and nights has thirty-one Swelter'd venom sleeping got, Boil thou first i' the charmed pot. ALL. Double, double, toil and trouble; Fire burn and cauldron bubble.