How does John Ford use imagery in 'Tis Pity She's a Whore?

The imagery reflects the humours. According to Humour psychology, the balance of four bodily fluids determines human personalities. Unusual or "humourous" people have an imbalance in either blood, phlegm, yellow bile, or black bile. Too much blood makes a person sanguine, happy and amorous; yellow bile makes a person choleric, stubborn, and impatient; too much phlegm results in a phlegmatic personality—dull and cowardly; while excesses of black bile made a person melancholy, introspective, and sentimental.

Robert Burton, whose Anatomy of Melancholy explores the relationship between love and the humours, strongly influenced Ford. The theory also aids in the categorization of various Renaissance characters (in Shakespeare, for example, Hamlet is melancholy, Hot Spur is choleric, etc.). In time, the Comedy of Humours developed, which pokes fun at characters driven by one aspect of their personalities, resulting in the meaning of the word humor today.