In 1875 the British Medical Journal had some fun digging around in the archives:
BARBAROUS PUNISHMENT: A SURGEON’S OCCUPATION. – 1720, March 29th. On Wednesday, Thomas Hayes, formerly the commander of a merchantman, stood in the pillory at Charing Cross, for the hour of twelve to one, when a surgeon, attended by the prison officers, got upon the pillory, when Mr. Hayes sat down in a chair placed for that purpose, and then the surgeon with a dressing-knife cut his left ear entirely off, delivered it into his own hands, and then the officer took it from him and betwixt his finger and thumb held it up to the view of the spectators, pursuant to his sentence at the Court of King’s Bench for forging a bond of £560, upon Mr. Edward Longbotham, also formerly the commander of a merchantman. He was a plain elderly man with grey hair, and was not pelted by the populace, which was very numerous.
1728, February 22nd. On Tuesday, came on before the Lord Chief Justice Raymond, at Westminster, the trial of Japhet Crook, alias Sir Peter Stranger, upon an indictment for forging two deeds of conveyance to himself, of an estate in Essex belonging to Mr. Joseph Garbutt, and afterwards for mortgaging the estate as his own for £2,500. After a hearing of about four hours, the jury brought him in guilty of the indictment; which being grounded on a statute of Elizabeth, he is to be put into the pillory, to have both his ears cut off by a surgeon, then his nostrils to be slit, and to suffer perpetual imprisonment.
I’m pretty sure there’s nothing about cutting off criminals’ ears in the Hippocratic oath…