In As You Like It, Le Beau gives some friendly advice to Orlando:

Good sir, I do in friendship counsel you
To leave this place. Albeit you have deserv’d
High commendation, true applause and love,
Yet such is now the duke’s condition
That he misconstrues all that you have done.
The duke is humorous: what he is indeed,
More suits you to conceive than I to speak of.

The duke is humorous? He doesn’t sound very humorous to me. Can we get a Shakespeare Follow-Up?

The “humours” referred to four bodily fluids that were believed to affect one’s mood and personality: blood, phlegm, yellow bile, and black bile. This was a theory that traced back as far as the ancient Greeks, and it was widely accepted in Shakespeare’s time. An imbalance of any one of these fluids in a person would have a particular effect. So, the duke is moody, not funny. And this use of the word is fairly consistent across the canon. So when Antipholus of Syracuse says he is not in a “sportive humour,” or Benedick says “a college of witcrackers cannot flout me out of my humour,” or Petruchio says “I’ll curb her mad and headstrong humour,” none of them are talking about the funny.

It’s clearly a retrochronism, but understanding a little bit about the humors can actually shed some light on quite a few lines in Shakespeare, so let’s review.

An excess of blood was thought to make you sanguine, and the cheerfully happy word actually comes from the Latin for bloody. So when Sir Toby Belch asks “Am not I consanguineous? am I not of her blood?,” he is using the term to describe a blood relationship.

Phlegm leads to quiet rationality. Kant actually thought it was the absence of temperament. Mistress Quickly therefore misapplies the term in The Merry Wives of Windsor when she beseeches Doctor Caius to “be not so phlegmatic.” She is trying to calm his anger down. She should have said “choleric.”

Choler stems from yellow bile (from the Greek “chole” for bile), and the word appears frequently in Shakespeare to describe anger or bellicosity. The black (“melan-“) variety of bile (“chole”) was also a frequently used theme. I’ve already written about melancholy in Shakespeare in an earlier post, so I don’t need to repeat it all here. The important thing to remember is that Shakespeare and his audience would have believed that these moods were caused by an imbalance of fluids. This is why bloodletting was such a popular medical practice; they believed they could remove the excess humours by drawing blood or applying leeches.

A poetic reference to bloodletting appears in King Richard II, as Richard attempts to sooth the conflict between Bolingbroke and Mowbray:

Wrath-kindled gentlemen, be rul’d by me;
Let’s purge this choler without letting blood:
This we prescribe, though no physician;
Deep malice makes too deep incision:
Forget, forgive; conclude and be agreed,
Our doctors say this is no month to bleed.

The complainants are seeking a duel, another way to purge choler by letting blood. Richard reframes their grievances as merely an imbalance of yellow bile, and uses the bloodletting metaphor to advocate a more peaceful solution. (It doesn’t work.)

In the 19th century, humours and bloodletting fell out of fashion as medical science developed a better understanding of human biochemistry. Apparently, though, the idea of the four humors survives today as a popular screenwriting technique.

On a somewhat-unrelated final note, do you know why the “funny bone” got its name? Because it’s the humerus! And I hope you find that humorous.