THURIO And how quote you my folly?
VALENTINE I quote it in your jerkin.
THURIO My jerkin is a doublet.
VALENTINE Well then, I’ll double your folly.
THURIO How?
SILVIA What, angry, Sir Thurio? Do you change colour?
VALENTINE Give him leave, madam. He is a kind of chameleon.
THURIO That hath more mind to feed on your blood, than live in your air.
VALENTINE You have said, sir.
THURIO Ay, sir, and done too, for this time.
VALENTINE I know it well, sir. You always end ere you begin. (2.4.18-28)
And how quote you my folly? asks Thurio, aggrieved; on what basis are you calling me a fool? I quote it in your jerkin, is Valentine’s comeback: on the basis of the ridiculous jacket you’re wearing. (Quote is perhaps punning on coat; Valentine’s caught Speed’s quibble-mania.) Excuse me, replies Thurio, I think you’ll find my jerkin is a doublet. There might be a slight class aspect here—doublet as posher than jerkin—but also a sneer at the young man from Verona, unused to Milanese sophistication: honestly, don’t you know anything about fashion? (A jerkin is likely less structured, and could be without sleeves; a doublet more likely to be finely tailored and fitted.) Well then, I’ll double your folly: so, doublet is mostly setting up double (in this play of pairs and duplicity and doubling-up), and here, in that case, I’ll show you even more what a fool you are. Double or nothing.
How? asks Thurio. Fashionable gentleman or not, he can’t keep up. Silvia makes a helpful (not) intervention (can she be enjoying this? if so, it doesn’t make her look particularly good): what, angry, Sir Thurio? Do you change colour? Ooooo, testy. Getting a bit hot and bothered? Valentine suspects he has the advantage here, presses it home: give him leave, madam (a bit of patronising faux courtesy); after all, he is a kind of chameleon. He’s a LIZARD who changes colour all the time… and also, he’s inconstant, unstable, lightweight. Thurio is, predictably, needled by this, as he’s meant to be: well, if I’m a chameleon, then I’m the kind of chameleon that hath more mind to feed on your blood, than live in your air. Do you want to take this outside? Do you want to fight me? I’d rather fight you than have to spend any more time with you, or even near you. (This is also referencing the belief that chameleons didn’t eat but rather lived by breathing alone.)
You have said sir: Valentine’s playing it cool, playing it smooth, courteous and ironic. Whatever; I can’t be bothered commenting. Keep yapping on, little man. Ay, sir, and done too, for this time. Yes, well, fine, that’s my final word, is all Thurio can manage. Valentine knows he’s won this little bout, although not with any great style: I know it well, sir (mock sympathetic, smug, conciliatory), because you always end ere you begin. You’re all talk, but you never even make it out of the blocks, do you? always on the back foot, a loser even before you open your mouth. And you’re not really serious about challenging me to a duel—just like you’re not capable—ahem—in other ways, that little ‘premature’ problem you’ve clearly got.