Green’s Dictionary of Slang

bit by... phr.

drunk; in combs. below.

In phrases

bit by a barn-mouse (also bit by a barn weasel) [? the barn-mouse consumes barley, from which beer is brewed]

drunk.

[UK]Eighth Liberal Science n.p.: No man must call a Good-fellow Drunkard [...] But if at any time they spie that defect in another, they may without any forfeit or just exceptions taken, say, He is Foxt, He is Flaw’d, He is Fluster’d, He is Suttle, Cupshot, Cut in the Leg or Back, He hath seen the French King, He hath swallowed an Hair or a Taven-Token, he hath whipt the Cat, He hath been at the Scriveners and learned to make Indentures, He hath bit his Grannam, or is bit by a Barn Weasel.
[UK]Head Canting Academy (2nd edn) n.p.: No man ought to call a Good-fellow a Drunkard; but [...] he may without a forfeit say he [...] is bit by a barn Weesel, &c.
[UK] ‘The Art of Drinking’ in Wit’s Cabinet 138: He has been bit by a Barn-weasel.
[UK]Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Barn Mouse bit by a Barn Mouse. Tipsey probably an allusion to Barley.
[UK]Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn) n.p.: Bit by a barn mouse, tipsey, probably from an allusion to barley.
[UK]Lex. Balatronicum.
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.
[UK]‘William Juniper’ True Drunkard’s Delight 225: Our tippler [...] has been bit by a barnmouse.