from Macbeth
by William Shakespeare
Double, double toil and trouble;
Fire burn and caldron bubble.
Fillet of a fenny snake,
In the caldron boil and bake;
Eye of newt and toe of frog,
Wool of bat and tongue of dog,
Adder's fork and blind-worm's sting,
Lizard's leg and howlet's wing,
For a charm of powerful trouble,
Like a hell-broth boil and bubble.
Double, double toil and trouble;
Fire burn and caldron bubble.
Cool it with a baboon's blood,
Then the charm is firm and good.
At a time when people actually believed in witches (and, more to the point, feared them), Shakespeare put three of them on the stage. Scholarly discussion over the years seems to support the idea that ol' Will wasn't just making up a rigmarole for his characters to recite, either. Like Ben Jonson's Alchemist or Kit Marlowe's Doctor Faustus, who spout historically accurate pseudo-science, the witches' mention of items in the brew seem to be of things that were part of the supposed pharmacopeia of witchery.
Given his audience's beliefs, the scenes with the witches would have had a lot more impact for them than they do for us, where all too often the three weird sisters come off a little campish.