Macbeth: Is this a dagger which I see before me,

The handle toward my hand?

Come, let me clutch thee.

I have thee not, and yet I see thee still.

Art thou not, fatal vision, sensible

To feeling as to sight? or art thou but

A dagger of the mind, a false creation,

Proceeding from the heat-oppressed brain?

Lady Macbeth: I see thee still,

And on thy blade and dudgeon gouts of blood,

Which was not so before.

There's no such thing:

It is the bloody business which informs

Thus to mine eyes.