What is a cynic? A man who knows the price of everything and the value of nothing. And a sentimentalist, my dear Darlington, is a man who sees an absurd value in everything, and doesn't know the market place of any single thing.
We are all in the gutter, but some of us are looking at the stars. We all have clouds above us but some see their silver linings. We all face difficulties but some of us are grateful that they aren't worse.
Just as the orator marks his good things by a dramatic pause, or by raising and lowering his voice, or by gesture, so the writer marks his epigrams with italics, setting the little gem, so to speak, like a jeweler.