The staging of this scene is made clear by the first ten lines of the scene. The gentlewoman's description of how Lady Macbeth has sleepwalked in the past acts as a stage direction for the actress playing Lady Macbeth. Her agitated reading of a letter is of course a visual reminder of her reading of the fateful letter in Act I, Scene 5. More than this, Lady Macbeth is seen to rub her hands in a washing action that recalls her line "A little water clears us of this deed" in Act II, Scene 2. If these words are not enough to arouse the Doctor's suspicions, those that follow must suggest to him not only that she is suffering but also the reason for that suffering.
Lady Macbeth's speech has become fragmented and broken by an enormous emotional pressure: the suave hostess and cool, domineering wife has been reduced to a gibbering creature whose speech (almost) signifies nothing. There are no logical connections between her memories or her sentences, and indeed, the devastation of her mind is so complete that she cannot recall events in their correct order. For example, "Out damned spot" is followed by "The Thane of Fife had a wife," referring to Lady Macduff. Later we hear the line "Banquo's buried: he cannot come out on's grave," and finally she believes she hears Macduff knocking at the gate. It is as though all the individual murders have coalesced into one seamless pageant of blood. Perhaps the most ironic line is the one which near-perfectly echoes an earlier line of Macbeth's. When Lady Macbeth cries "all the perfumes of Arabia will not sweeten this little hand," we must not forget that she was not on stage to hear her husband's "Will all great Neptune's ocean wash this blood / Clean from my hand?" (Act II, Scene 2).
