Green’s Dictionary of Slang

a phr. used to refute a suggestion or hypothesis; usu. preceded by If that’s... then I’m a...

[c.1597		Shakespeare Henry IV Pt 1 II iv: peto.: No, no, they were not bound. fal.: You rougue they were bound, every man of them; or I’m a Jew else, an Ebrew Jew].
1785		M. Lonsdale Spanish Rivals I iii: Rat the man’s assurance! If I know what to make of him I’m a nun.
1795		Sporting Mag. Mar. V 323/1: I am a Dutchman if it [i.e. a small jug of ale] is not the least of its age that ever I saw in my life.
1818		‘A. Burton’ Adventures of Johnny Newcome III 126: A man of war — or I’m a Tailor!
1825		‘All England Are Slanging It’ Universal Songster I 39/2: As sure as I’m a Dutchman, you’ve been drinking a little too much Hollands and water.
1831		R. Ryan Everybody’s Husband I i: That makes four wives or I’m a Dutchman.
1834		W.A. Caruthers Kentuckian in N.Y. I 96: I’m a Turk if I ain’t tetotally dished.
1837		Marryat Snarleyyow II 212: ‘Howsomever, I have nothing to say, but I wish you, luck; but if you kill that dog, I’m a bishop – that’s all’. ‘And if I don’t try for to do so, I am an harchbishop, that’s all,’ replied the gallant Smallbones.
1838		‘Nights At Sea’ Bentley’s Misc. Apr. 589: I’m a tinker if he didn’t shell out a guinea to get off.
1842		Leeds Times 25 June 7/1: I’ve come to spiflicate you if you won’t be quiet; and if I don’t I’m a Dutchman.
1850		F.E. Smedley Frank Fairlegh (1878) 278: If this ain’t taking the change out of old Vernor, I’m a Dutchman.
1867		M. Lemon Golden Fetters II 185: If she did not love that man, why — I’m a Dutchwoman.
1876		G. Lander Little Gerty III i: If she isn’t bowlder than brass, I’m a Dutchman!
1884		J. Miller Memorie and Rime 146: If I don’t sell out to that old duffer this time [...] I’m a Dutchman.
1889		B. Mitford Fire Trumpet I 52: Ethel will lead you a life of it, or I’m a Trojan.
1896		G.M. Fenn Sappers and Miners 90: Well, if you young gents can’t tell a good slumper, I’m a Dutchman.
1897		A.H. Lewis Wolfville 240: ‘I’ma Chinaman,’ says Billy, ‘if it ain’ta kid!’.
1900		A.H. Lewis ‘Politics’ Sandburrs 96: I’m Dutch if he don’t up an’ sink his hooks in it.
1901		Essex Newsman 6 Apr. 2/6: Those slices of ‘beef’ were almost as tough as shoe leather and if they were not horseflesh, I’m a Dutchman.
1907		W.M. Raine Bucky O’Connor (1910) 214: I’m a Chink if he ain’t carryin’ them same two guns I took offen him.
1916		J. Buchan Greenmantle (1930) 359: If he finds an operator before the evening I’m the worst kind of a Dutchman.
1925		Dos Passos Manhattan Transfer 160: That was a rotton [sic] show or I’m a Dutchman.
1933		(con. WWI) F. Richards Old Soldiers Never Die (1964) 227: If he don’t get the Victoria Cross for this stunt I’m a bloody Dutchman.
1942		Dundee Eve. Teleg. 5 Aug. 8/5: ‘She was starring or I’m a Dutchman’.
1954		Picture Post (ad for Burton tailoring) 13 Nov. 35: It’s a honeymoon, my dear Watson, or we’re a Dutchman!
1967		F. Sargeson Hangover 97: The beautiful cake was homemade (or she was a Dutchman).
1977		T. Berger Who is Teddy Villanova? 20: If he was not as dead as cold lasagna [...] I was a Dutchman.