Lear orders Kent to take a letter to Regan (via Gloucester it seems). After Kent leaves, the Fool calls Lear a fool for growing old without growing wise. Lear ends the short scene with, “let me not be mad, not mad . . . I would not be mad.”
ACT I. SCENE V. Court before Albany’s palace.
Enter Lear, Kent, Gentleman, and Fool
Go you before to Gloucester with these letters.
Acquaint my daughter no further with anything you
know than comes from her demand out of the letter.
If your diligence be not speedy, I shall be there afore you.
I will not sleep, my lord, till I have delivered your letter. Exit 
If a man’s brains were in’s heels, were’t not in
danger of kibes?
KING LEAR Ay, boy.
Fool Then, I prithee, be merry; thy wit shall ne’er go
KING LEAR Ha, ha, ha.
Shalt see thy other daughter will use thee kindly,
for though she’s as like this as a crab’s like an
apple, yet I can tell what I can tell.
KING LEAR Why, what canst thou tell, my boy? 
She will taste as like this as a crab does to a crab. Thou canst
tell why one’s nose stands i’ the middle on’s face?
KING LEAR No.
Why, to keep one’s eyes of either side’s nose; that
what a man cannot smell out, he may spy into. 
KING LEAR I did her wrong—
Fool Canst tell how an oyster makes his shell?
KING LEAR No.
Fool Nor I neither. But I can tell why a snail has a house.
KING LEAR Why? 
Why, to put his head in, not to give it away to his
daughters and leave his horns without a case.
I will forget my nature. So kind a father! Be my
Thy asses are gone about ‘em. The reason why the 
seven stars are no more than seven is a pretty reason.
KING LEAR Because they are not eight.
Fool Yes, indeed. Thou wouldst make a good fool.
KING LEAR To take ‘t again perforce—monster ingratitude!
If thou wert my fool, nuncle, I’d have thee beaten 
for being old before thy time.
KING LEAR How’s that?
Fool Thou shouldst not have been old till thou hadst been wise.
O, let me not be mad, not mad, sweet heaven
Keep me in temper. I would not be mad. 
How now, are the horses ready?
Gentleman Ready, my lord.
KING LEAR Come, boy.
She that’s a maid now, and laughs at my departure,
Shall not be a maid long, unless things be cut shorter.