The significance of the two buckets of filth that Iago carries lies in the connection that he himself makes between his former state and his present condition, which of course represents a massive fall in society from being a loyal and trusted officer of one of the most important generals of the time to being a character who is only allowed to carry excrement in buckets. Note what Iago himself says:
Othello seeks to hide the grisly news
that he did almost kill his guiltless wife,
so dares not gut me openly in law,
but decorates my service with a mean and stinking
From Iago's perspective, his present condition relates to Othello's inability to face up to his own homicidal feelings, and he blames what has happened to him entirely on the character of "the pedant," or Constance, who is of course largely responsible for his fall from grace. However, at the same time, symbolically it is possible to identify further significance in Iago's condition. He is bearing these two buckets of filth "on a yoke," and a "yoke" is something that is a well-known symbol of enslavement and servitude. The fact that he is carrying "two buckets of filth" could represent his own jealousy and hatred, that enslave him to his present course of trying to gain revenge. Macdonald therefore presents Iago in a way that strongly suggests he is an enslaved character by his own thoughts and feelings.
Compare the language and style of Constance's soliloquy at the end of Act I, scene i (from "Regina..." to "...the world of a favour") with the language and style of her soliloquy at the end of Act III, scene i (from "Thank God" to "a convent around here somewhere").
MacDonald employs both verbal and physical comic devices in Act III, scene iv. Identify two of each and evaluate their relative success
In Act II, scene ii, MacDonald's Iago enters carrying two buckets of filth. Discuss the dramatic and thematic purposes of this device.