Lady Macbeth may be cool as an evil cucumber by day, but as we see in Act IV, she reveals her humanity—and her sense of guilt—while sleepwalking. To understand just how profoundly her deeds have affected her, listen first to Track 16, right at the moment that her husband is murdering King Duncan. “Regna il sonno su tutti,” she sings—“Sleep reigns over all.” Then, twice, we hear the mournful sound of a horn. To Lady Macbeth, this is the lament of an owl—“Risponde il gufo al suo lugubre addio! [The owl replies to his mournful farewell]. As Macbeth returns, she plants the seed of her own remorse, briefly wondering whether Duncan was aware of his own murder: “Ch’ei fosse di letargo uscito/Pria del colpo mortal?” [What if he was roused from his sleep before the fatal blow?]
Now play Track 17, a brief portion of Lady Macbeth’s sleepwalking scene. This is a fine example of the blending of vocal and instrumental music to convey complex operatic moods. As Lady Macbeth sings “Una macchia è qui tuttora/Via, ti dico” [There’s still a spot here/Away, I tell you—the equivalent of Shakespeare’s famous “Out, damned spot! Out I say!”], two instrumental figures repeat again and again. One, heard from the string section, represents her repeated attempts to rub the blood from her hands. The other? That horn again—reminding us that deep within Lady Macbeth’s unconscious lurks the memory of the moment Duncan met his death, when an owl cried out in the night.