Menaechmus II is walking along the street with the dress. The Wife sees him holding the dress and decides she will give him the welcome he deserves. She accosts him and calls him a scoundrel for carrying that dress around in her sight. Menaechmus II is stunned by this comment and calls her a witch like Hecuba for her behavior. When she claims she will get a divorce, he tells her go ahead.
The Wife says she is going to send a slave to get her father and tell him how outrageously Menaechmus II has behaved—he’s stolen her dress and jewelry and given them to his mistress. She sees her father coming toward her and asks Menaechmus II if he knows the man. He replies snarkily that he remembers meeting him at the same time as he met Methuselah.
The Father enters the scene and grumbles about how he can only walk so fast given his old age. He is annoyed that his daughter has summoned him because she and her husband have had a row. He believes wives are mostly to blame even though he does concede there are boundaries for husbands.
The Father asks the Wife what has happened and then tells her she must humor her husband, and that the more she annoys him, the more he’ll turn to Erotium. Menaechmus I gives her clothes and jewelry and so she “shouldn’t be so fussy about things” (89). She should not slander her husband, and he will take it upon himself to ask Menaechmus II about things.
The Father approaches Menaechmus II and asks him to explain his behavior, to which Menaechmi II hotly protests that he has done nothing wrong. He also does not know who the Father is, and resents his questions. Finally, he decides he will just pretend to be crazy so they will leave him alone.
In order to accomplish this, he starts saying an oracle from Apollo has declared that he burn the Wife’s eyes out and punch her face. The Wife and Father are horrified, and the Wife goes into her house.
Menaechmus II threatens the Father with violence and the Father is convinced Menaechmus II is deeply ill. He leaves to fetch a doctor.
Menaechmus II decides now that he’s left alone, he should get back to the ship. He departs.
The Father complains that the Doctor is making him wait too long, but finally sees the Doctor coming his way.
The Doctor asks the Father what Menaechmus II’s illness is—is it hallucinations, or madness, or lethargy, or subcutaneous humors? The Father says he does not know and that is why the Doctor is here. He hopes the Doctor will spare no pains to find out what is wrong.
Menaechmus I enters, sighing that today is an odd day with his parasite and his mistress. The Father and the Doctor approach, but Menaechmus I insults the Doctor and he retreats. He whispers to the Father that this will be a hard case.
Turning back to Menaechmus I, he asks questions such as what wine he prefers, if his eyes ever harden, if he sleeps soundly, etc. Menaechmus I is indignant and annoyed with these questions, which convinces the Father and the Doctor there is something wrong with him. The Father tells the Doctor to apprehend his son-in-law and take him to his place so he can freely treat him. The Doctor says he will need multiple men to subdue the raving man. The Doctor hurries away, as does the Father.
Left alone, Menaechmus I is incredulous that he is accused of being crazy. He lives a normal life with normal people and has never been ill. He is not sure where to go or what to do.
Messenio enters, not seeing Menaechmus I. He is pleased with himself for being an excellent slave and for knowing how to avoid a beating. He knows pleasing his master is the right thing to do and he hopes to be rewarded before long. Having left the baggage and sailors at the inn as his master ordered, Messenio plans to see if he is still in Erotium’s lair.
The Father orders the slaves to pick up Menaechmus I and carry him to the Doctor’s place. He departs to get there first.
The slaves surround Menaechmus I and he yells for help. Messenio espies this and rushes over. Messenio declares he will be his helper, defender, and ally, and begins scuffling with the men. Finally the slaves drop Menaechmus I and run away, afraid of a further beating from Messenio,.
Messenio asks if he can go free for saving his master’s life, but Menaechmus I, confused, says he is not his master. Messenio asks that “if you say I don’t belong to you, let me go free,” to which Menaechmus I replies, “So far as I am concerned, I declare you free to go anywhere you want” (98). Messenio is thrilled and says he will continue to live by choice with Menaechmus I and serve him.
Now, though, Messenio will go get his baggage and money, which the bemused Menaechmus I encourages him to do.
After Messenio leaves, Menaechmus I muses that so many strange things have happened to him today. He decides to try Erotium again.
Menaechmus II and Messenio enter, the former angry at the latter. Messenio declares he rescued him and was set free, but Menaechmus II scowls that he’d rather be a slave himself than set Messenio free.
Menaechmus I comes out of Erotium’s house. Messenio sees the two identical men before him and gasps. Menaechmus II concedes the man looks a bit like him. Both say their names are Menaechmus, both say they are from Sicily. Messenio explains how he was freed.
The men go in circles for a bit, saying they are both Menaechmus, son of Moschus. Suddenly, Messenio has an epiphany—this must be the twin brother. He asks who brought him here, and then pulls Menaechmus II, who answers in the affirmative, aside. He tells him that this man is his twin whom he vowed to find. Menaechmus II tells Messenio that if he can prove this man is his brother, then Messenio will be freed.
Messenio tells Menaechmus I that his intent is to prove the men are brothers and he will ask him questions. Menaechmus I assents. Messenio asks what his name was, where he is from, the earliest thing he remembers from Sicily, how old he was when he was on the ship with his father, and what the twin brother he remembered having was named.
Menaechmus I answers everything honestly and, legitimating the relationship, embraces his twin brother. They laugh over the mistaken identities and Menaechmus II officially grants Messenio his freedom.
The brothers decide to both go back to Syracuse, and Menaechmus I plans to auction off all his Epidamnus property. Messenio asks if he can be auctioneer and Menaechmus I agrees.
The brothers go in the house and Messenio announces loudly that there will be an extraordinary auction in a week in which Menaechmus I will sell his property for cash and the Wife can go too if anyone takes a fancy to her. He turns to the audience and bids them applaud the actors.
The mistaken identities and ensuing hijinks continue apace in this last act, with two new characters—the Doctor and the Father—entering the action. The Father immediately renders himself unlikeable to modern audiences with his comments on how wives have to pretty much do whatever their husbands want to do and turn a blind eye to their follies, but for Greek and Roman audiences, he would have been an amusing curmudgeon. He advises his daughter, “humour your husband; don’t always have your eye on what he’s doing, where he’s going, what he’s up to” (89) and that “he keeps you in clothes and jewelry, and gives you proper food and service, and so you oughtn’t be so fussy about things, my girl” (89).
The Father has more of a direct effect on the narrative when he encounters Menaechmus II, who, annoyed with the confusion resulting from the mistaken identities and the haranguing of the Wife, pretends he is crazy. The Father decides he must procure the Doctor to help his son-in-law: “A violent and severe disease! . . . The gods preserve us from the like. See now, how strong he was a moment since, and now is mad with sudden access [sic] of disease” (92). Coupled with his son-in-law’s theft of the dress, the madness means that Menaechmus II is no longer fit for society. Scholar Eleanor Winsor Leach explains, “[The Father’s] support of his son-in-law’s follies is contingent on the young man’s observance of certain rules. Adultery is tolerable, but not the theft of the matron’s palla . . . If Menaechmus is insane, he is upsetting the social balance, and the old man readily consigns him to literal captivity.”
In her article on the madness and medicine in the play, Lydia Baumbach explains that what otherwise seems like a straightforward farce of mistaken identity actually has a great deal of information on what the ancients thought about madness. She begins by looking at the symptoms proffered by the characters in regards to Menaechmus II’s madness: green, glittering eyes, which would reference an excess of bile, the cause/concomitant of madness; his gaping and gesticulating; and his references to Bacchus, a god commonly associated with the dissolute and frenzied.
The Doctor then asks specific questions of him, which can seem puzzling to the modern reader. The one about Menaechmus II’s arm being uncovered and that being bad for his condition may be “a way of poking fun at the doctor by making him ask a silly question,” but the other questions are rooted in Greek medicine. The eyes that the Doctor asks about are “perhaps the first thing that betray madness,” and the subsequent cursing and raving of Menaechmus II also pragmatically leads him to conclude the man is mad.
Plautus’s depiction of the Doctor is also an interesting one, Baumbach explains. Plautus “certainly pokes fun at him, and seems to share the prejudice which many Romans felt about Greek doctors.” The Father complains about the Doctor’s waiting room and finds him perhaps boastful. He also seems “very confident that he will be able to affect a cure easily” but then, after been tasked with apprehending Menaechmus II and bringing him back to his house, dumbly leaves to prepare things. Baumbach notes that the Doctor “is guilty either of negligence or foolishness here—or both.”