Will Ladislaw leaves for Europe, and Mr. Casaubon and Dorothea complete their plans for the wedding and honeymoon.
They're planning to honeymoon in Italy, but it's going to be a working trip for Mr. Casaubon – he'll spend most of his time in libraries and museums, studying.
He says that he wishes Celia could come along to keep Dorothea company, and Dorothea's annoyed that he thinks that she'd even need company, or mind being alone, if it meant that he'd be able to get his precious work done.
Mr. Casaubon doesn't notice that she's at all annoyed.
As she gets dressed for dinner, she convinces herself that he was right, and she was wrong, and is no longer irritated.
There are a lot of guests for dinner that night, and some of the men discuss Dorothea's beauty amongst themselves. Another woman is brought up, by way of comparison – the lovely Miss Vincy, who is more of a flirt than either Dorothea or Celia. Some of the men present prefer a flirt, and say so. Luckily Mr. Vincy (the young lady's father) isn't nearby to overhear.
Meanwhile, some of the older women in the group are discussing their various health problems and the relative merits of the doctors in the town. One of them brings up Mr. Lydgate, the new young surgeon who's just moved to Middlemarch. He's also at the party, but out of earshot, so they can discuss him openly. He has "new ideas" about the medical profession. The ladies are of mixed opinion about those new ideas, but they all agree that he's a "gentleman" and talks well.
Lydgate isn't asked, but he'd be in the same camp as the guys who prefer the flirty Miss Vincy to the more serious-minded Dorothea Brooke.