What wouldst write of me if thou shouldst praise me?

Desdemona
What wouldst write of me if thou shouldst praise me?
Iago
O, gentle lady, do not put me to ‘t,
For I am nothing if not critical.
Desdemona
Come on, assay.—There's one gone to the harbor?
Iago
Ay, madam.
Desdemona, aside
I am not merry, but I do beguile
The thing I am by seeming otherwise.—
Come, how wouldst thou praise me?
Iago
I am about it, but indeed my invention comes
from my pate as birdlime does from frieze: it
plucks out brains and all. But my muse labors, and
thus she is delivered:
If she be fair and wise, fairness and wit,
The one's for use, the other useth it.
Desdemona
Well praised! How if she be black and witty?
Iago
If she be black, and thereto have a wit,
She'll find a white that shall her blackness hit.
Desdemona
Worse and worse.
Emilia
How if fair and foolish?
Iago
She never yet was foolish that was fair,
For even her folly helped her to an heir.
Desdemona
These are old fond paradoxes to make
fools laugh i' th' alehouse. What miserable praise
hast thou for her that's foul and foolish?
Iago
There's none so foul and foolish thereunto,
But does foul pranks which fair and wise ones do.
Desdemona
O heavy ignorance! Thou praisest the
worst best. But what praise couldst thou bestow on
a deserving woman indeed, one that in the authority
of her merit did justly put on the vouch of very
malice itself?
Iago
She that was ever fair and never proud,
Had tongue at will and yet was never loud,
Never lacked gold and yet went never gay,
Fled from her wish, and yet said “Now I may,”
She that being angered, her revenge being nigh,
Bade her wrong stay and her displeasure fly,
She that in wisdom never was so frail
To change the cod's head for the salmon's tail,
She that could think and ne'er disclose her mind,
See suitors following and not look behind,
She was a wight, if ever such wight were—
Desdemona
To do what?
Iago
To suckle fools and chronicle small beer.
Desdemona
O, most lame and impotent conclusion!
—Do not learn of him, Emilia, though he be thy
husband.—How say you, Cassio? Is he not a most
profane and liberal counselor?
Cassio
He speaks home, madam. You may relish him
more in the soldier than in the scholar.
Cassio takes Desdemona's hand.
Iago, aside
He takes her by the palm. Ay, well said,
whisper. With as little a web as this will I ensnare as
great a fly as Cassio. Ay, smile upon her, do. I will
gyve thee in thine own courtship. You say true, 'tis
so indeed. If such tricks as these strip you out of
your lieutenantry, it had been better you had not
kissed your three fingers so oft, which now again
you are most apt to play the sir in. Very good; well
kissed; an excellent courtesy! ‘Tis so, indeed. Yet
again your fingers to your lips? Would they were
clyster pipes for your sake! Trumpets within.
The Moor. I know his trumpet.
Cassio ‘Tis truly so.
Desdemona Let's meet him and receive him.