"And There's a Humor of it" is a new exhibit showing at the University of Arizona's Health Sciences Library highlights the presence of an old medical theory known as The Four Humors in the works of William Shakespeare.

While the theory originated in the ancient middle east, it found its place in the science and popular culture of the educated class in Victorian England.

The theory stated that the body's fluids could be broken down into four categories: black bile, phlegm, yellow bile, and blood, and a well-balanced person would contain equal amounts of each. A person who contained more or less than needed of any humor would have an altered personality.

University of Arizona Professor Fred Kiefer has spent much of his time studying Shakespeare, and went through the exhibit and described how the four humors showed up in Shakespeare's work and what they meant to those living at the time of The Bard of Avon.