How we cite our quotes: (Book.Chapter.Paragraph)
Quote #1
'I'm thinking of his mother,' said Strether after a moment. 'He has darkened her admirable life.' (2.1.19)
Way back at the beginning of this book, Strether firmly agrees with Mrs. Newsome that Chad is an irresponsible little jerk and that he has tainted Mrs. Newsome's "admirable" life by taking off to Paris. Of course, no one knows what Chad is actually doing in Paris. But at this point, Strether admires Mrs. Newsome so much that he assumes anything keeping Chad away from her must be evil in some way.
Quote #2
It was a question, he indicated, that there might be several ways of taking; but he decided after an instant for the humorous. 'Haven't I sufficiently showed you how I admire any pretty girl?' (2.1.213)
When Maria Gostrey asks him if he admires Mamie Pocock, Strether totally dodges the question and jokes that he admires all pretty young women. But what he's actually saying through his silence is that he mostly thinks of Mamie as eye candy and doesn't necessarily respect her. That'll change once he gets to know her better. But for the time being, he doesn't think much of her beyond her physical beauty.
Quote #3
The new quantity was represented by the fact that Chad had been made over. (4.1.4)
When he first encounters Chad, Strether feels like his brain is broken. He has been so dead-set on finding Chad living a terrible life of sin that he can't even comprehend the fact that Chad has turned into a distinguished young gentleman. His admiration for Mrs. Newsome won't really allow him to accept Chad's makeover at first. But over time, Strether will learn to admire Chad even more than Mrs. Newsome.