Green’s Dictionary of Slang

port wine n.

blood.

c.1790		‘Kilmainham Minit’ in A. Carpenter Verse in Eng. in 18C Ireland (1998) 436: Oh! twas den me port Royal run cold.
1858		A. Mayhew Paved with Gold 189: Ned sent his ‘hard dumplings’ against Jack’s ‘organ-pipes,’ and upset the ‘port wine’, the blood squirting from the nose in such quantities.