"If you pick up a starving dog and make him prosperous, he will not bite you. That is the principal difference between a dog and a man." -- Mark Twain.
“There’s a professor here that’s famous for Mark Twain,” Pickering said. “He’s been written up. You like Twain?”
“You know what Twain said about dogs, don’t you? You pick up a starving dog and make him prosperous, he won’t bite you. That’s the difference between a dog and a man.”
“Yes, sir. I remember that.”
“He got bitter in his old age. Wanted to blow up the human race. Too bad. Maybe he was too smart. What do you think?”
“I think he went through a lot in his life. As famous as he was, maybe it was a disappointment to him.”