From Hamlet 2.2.

Hamlet. Slanders, sir; for the satirical rogue says here that old men have grey beards, that their faces are wrinkled, they eyes purging thick amber and plum-tree gum, and that they have a plentiful lack of wit, together with most weak hams; all of which, sir, though I most powerfully and potently believe, yet I hold it not honesty to have it thus set down, for yourself, sir, shall grow old as I am, if like a crab you could go backward.

Polonius. [Aside] Though this be madness, yet there is method in't--Will you walk out of the air, my lord?

The entirety of Hamlet
T.S. Eliot's essay on "Hamlet"