Green’s Dictionary of Slang

fox n.²

a state of drunkenness.

1700

N. Ward ‘A Step to Stir-Bitch-Fair’ in Writings (1704) 272: They get Drunk, Quarrel, and make Bargains, till the Fox brings ’em to Sleep, and Sleep, by the next Morning, to a Sober Repentance.

In compounds

fox-sleep (n.)

a drunken sleep.

1673

M. Stevenson Norfolk Drollery 13: They that before so great a noise did keep, / Now slept, and in the rightest sense, Fox-sleep.

In phrases

catch a fox (v.)

to be drunk.

c.1698		B.E. Dict. Canting Crew.
1673		M. Stevenson Norfolk Drollery 13: Some Fudle-cap sure came / Into the Room, and gave his own name. / How should he catch a Fox?