For the pictorial version go here. Warning! For Mature Audiences. Parental discretion advised.
Dryden in his "A Discourse concerning the Original and Progress of Satire," 1693:
How easie it is to call Rogue and Villain, and that wittily? But how hard to make a Man appear a Fool, a Blockhead, or a Knave, without using any of those opprobrious terms? To spare the grossness of the Names, and to do the thing yet more severely, is to draw a full Face, and to make the Nose and Cheeks stand out, and yet not to employ any depth of Shadowing. This is the Mystery of that Noble Trade; which yet no Master can teach to his Apprentice: He may give the Rules, but the Scholar is never the nearer in his practice. Neither is it true, that this fineness of Raillery is offensive. A witty Man is tickl'd while he is hurt in this manner and a Fool feels it not. The occasion of an Offence may possibly be given, but he cannot take it. If it be granted that in effect this way does more Mischief; that a Man is secretly wounded, and though he be not sensible himself, yet the malicious World will find it for him: Yet there is still a vast difference betwixt the slovenly Butchering of a Man, and the fineness of a stroak that separates the Head from the Body, and leaves it standing in its place. A man may be capable, as Jack Ketch's Wife said of his Servant, of a plain piece of Work, a bare Hanging; but to make a Malefactor die sweetly, was only belonging to her Husband. I wish I cou'd apply it to my self, if the Reader wou'd be kind enough to think it belongs to me.
Dryden compliments Ketch as the deft-handed model for us satirists, but the man was as slovenly a butcher as any called to our high office. He was famous for bungling his beheadings. In one case, having struck a nobleman five times with the axe, he had to cut off his client's head with a knife. He then wrote an Apologie in which he blamed his client for moving about and making him miss. I say client, because in those days it was customary for the condemned person to tip the executioner to make a quick, clean job of it. So, I wonder if Dryden is having his fun at the reader's expense. Or, whether, to the contrary, he means to suggest that we satirists should not be too quick to end our scenes, no matter how much we are tipped by our clients to do so. Our performance may be more morally instructive, as well as more comical, if lovingly prolonged. Then again, I may be just excusing my own ineptitude and sadism by finding a famous role model.