There is no conversation between Brutus and Calpurnia in Act 1, Scene 1 of Julius Caesar. You are probably referring to a conversation between Caesar and Calpurnia in Act 1, Scene 2. Calpurnia is Caesar's wife. Portia is Brutus's wife. Mark Antony is participating in a foot race which is held each year during a religious festival. Romans believed that a woman who wanted to conceive a child would be enabled to do so if struck with a goatskin thong by one of the runners. Caesar's wife is barren. He tells her: "Be sure to stand directly in Antonio's way / When he doth run his course." He tells Antony: "Forget not in your speed, Antonio, / To touch Calpurnia, for our elders say / The barren, touched in this holy chase, / Shake off their sterile curse." The inclusion of this dialogue seems intended mainly to introduce two characters: Calpurnia and Antony. Shakespeare derived the incident from an English translation of Plutarch's Lives of the Noble Grecians and Romans.