Dropsy is an out-of-date medical term for edema, which is an abnormal accumulation of fluid in a particular area of the body.
Lord Grantham says that Carson is being melodramatic and that he's "not playing Sidney Carton." Carton, a character in Charles Dickens' novel "A Tale of Two Cities," is at times alcoholic and depressed.
The episode won 3 Emmy Awards for Outstanding Costumes for a Miniseries, Movie or a Special, Outstanding Cinematography for a Miniseries or Movie and Outstanding Directing for a Miniseries, Movie or a Dramatic Special.
Robert mentions "Lloyd George's insurance measures," referring to the National Insurance Act 1911, which created National Insurance, a fundamental component of the welfare state in the United Kingdom. David Lloyd George, then the Liberal Chancellor of the Exchequer, was the primary moving force behind its design.
At 26:00, Thomas and Daisy dance the "grizzly bear," an early 20th-century dance style that originated in San Francisco. The dance was rough and clumsy. During the dance, the dancers would yell out: "It's a Bear!" The genuine Grizzly Bear step was a correct imitation of the movements of a dancing bear, moving or dancing to the side.