Corbaccio enters and asks Mosca why he is bleeding. Mosca explains that Corbaccio’s son, Bonario, somehow found out that Corbaccio was going to disinherit him, and so he hurt Mosca and promised he would kill Corbaccio and Volpone. Corbaccio exclaims that he will disinherit Bonario because of what he has done. As they talk, Voltore enters secretly, unnoticed by them.
Mosca once again demonstrates his ability to improvise by immediately convincing Corbaccio of a new lie. It’s ironic that Corbaccio says he’ll disinherit Bonario for the (fake) violent deeds, because the only reason that Corbaccio was there in the first place was to disinherit Bonario. Voltore’s unnoticed presence creates another layer of dramatic irony, because the audience sees him enter and knows that he, like the audience, can overhear Mosca and Corbaccio.
Corbaccio then asks Mosca how Volpone is doing and if he will die soon. Mosca says that he’s afraid Volpone will live past May, which Corbaccio mishears as ‘today.’ Corbaccio asks if Mosca can poison Volpone, but Mosca says no.
Corbaccio’s deafness reminds the audience about his age and infirmity, which in turn explains his request that Mosca poison Volpone. While the other suitors must work to appear like they care about Volpone’s health, Corbaccio can’t afford to because he simply doesn’t have time to waste. This suggests that when greed becomes more extreme and urgent, all senses of morality and keeping up appearances are superseded.
Voltore then steps forward, having seen Mosca apparently working with Corbaccio. Mosca is able to convince Voltore that he is only pretending to work for Corbaccio for Voltore’s benefit, saying that he convinced Corbaccio to name Volpone heir so that Voltore would inherit an even greater fortune when Volpone dies. He explains that he brought Bonario in to witness Corbaccio naming Volpone heir in the hopes that Bonario would become violent with Corbaccio. However, when Celia came in on an unexpected visit, Bonario seized her, wounded Mosca, and said that he’d murder Celia if she and Mosca didn’t swear that Volpone tried to rape her. Bonario has also apparently run out to accuse his father, to defame Volpone, and to defeat Voltore. Voltore tells Mosca to bring Corvino to court to stop Bonario’s plan. Corbaccio tries to listen in, but he can’t hear, so he just exits with Voltore. Volpone rises from bed and prays that Mosca is successful in weaving this intricate web of lies.
It’s possible that the reason Mosca gives for bringing Bonario to the house is true, but this also might just be a lie used to manipulate Voltore. Again, Mosca tells one of the suitors—this time Voltore—that part of his work to secure Volpone’s fortune for Voltore is to keep up appearances around Volpone and the other suitors. And again, while this reminds the audience that Mosca is a character in a play, ironically it does make Voltore realize that Mosca is acting around him. Mosca is able to convincingly pretend to be on Voltore’s side because Corbaccio can’t hear him, but also because Voltore stands to gain so much from Mosca’s help that he is blinded to the truth.