Green’s Dictionary of Slang

remedy critch n.

[SE remedy, ease + critch, an earthenware vessel; ult. cratch, a stable hayrack and thus a crèche; the term is used as such in early descriptions of Christ’s birth]

a chamberpot.

[UK]Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Remedy Critch a Chamber Pot.
[UK]Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn).
[UK]Lex. Balatronicum.
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.