In act 2, scene 1 of Julius Caesar, Portia points out that Brutus has been behaving strangely for some time. He has crept out of bed in the middle of the night. The prior day at supper he rose and wandered about abstractedly, refusing to tell Portia what was wrong and dismissing her "with an angry wafture of your hand." Brutus tells her that he is unwell, but Portia refuses to accept this explanation, saying:
Brutus is wise, and, were he not in health,
He would embrace the means to come by it.
Such means, she points out, would scarcely include leaving his bed in the middle of the night
To dare the vile contagion of the night
And tempt the rheumy and unpurged air
To add unto his sickness?
Portia surmises that it is not Brutus's body but his mind that is afflicted. Six or seven men have come to see Brutus tonight, hiding their faces even in the midst of darkness. This must clearly have something to do with Brutus's perturbation. It is because of this meeting that Brutus has "some sick offence" within his mind. Portia demands that Brutus confide in her what is troubling him. She is his wife and ought to share his secrets. She reasons that if he does not trust her enough to tell her what is troubling him, she is no more than a "harlot" to him. In fact, Portia is exactly right in her diagnosis, which shows that she is to be trusted for her intelligence, loyalty, and capacity to help Brutus in his dilemma.