Blissett, William. "The Secret'st Man of Blood:
A Study of Dramatic Irony in Macbeth." SQ 10 (1959). 1397-408.

Thesis: Blissett starts by saying that he wants to expand the definition of "dramatic irony" to include all instances in which "a speech fits into a pattern of imagery or system of significance of which the audience has a clearer and more complete awareness than the speaker" (398). He goes on to say that he will "try to indicate the way in which the ideas of air, blood, seed, and time are used structurally so as to become inextricably bound up with the action and to constitute a dimension of dramatic irony" (398).

Blissett's discussion of these four motifs emphasizes the instances in which what is said means more than the speaker knows. An example appears in Macbeth's speech of pretended grief over Duncan's death. Macbeth says, "Had I but died an hour before this chance, / I had liv'd a bless'd time, for from this instant, / There's nothing serious in mortality." Macbeth doesn't mean it, but it's true. Macbeth really thinks that the time to come, when he is king, will be blessed, but Blissett says that we understand that Macbeth's time as king will be cursed, so we see the dramatic irony.

In a more general remark about how dramatic irony is produced by Shakespeare's handling of the theme of time, Blissett says,

By the protagonists, time is made the object of an act of violence: an attempt is made to seize the future in the instant by catching a way nearer than the natural process of growth: Macbeth doth murder time. Time is indeed dead for him from that moment; and what he had been deluded and scolded into regarding as an assertion of potency leads at last only to the impotence of tomorrow and tomorrow and tomorrow.  (407)
Evaluation: Blissett more-or-less assumes that every member of the audience of Macbeth knows the play as well as he does; nevertheless, he provides a valuable study of four important motifs.

Bottom Line: A good academic essay.