Mr. Grex of Monte Carlo by E. Phillips Oppenheim

Lady Weybourne was lunching on the terrace of Ciro's restaurant with her brother. She was small, dark, vivacious. Her friends, of whom she had thousands, all called her Flossie, and she was probably the most popular American woman who had ever married into the English peerage. Her brother, Richard Lane, on the other hand, was tall, very broad-shouldered, with a strong, clean-shaven face, inclined by disposition to be taciturn. On this particular morning he had less even than usual to say, and although Lady Weybourne, who was a great chatterbox, was content as a rule to do most of the talking for herself, his inattention became at last a little too obvious. He glanced up eagerly as every newcomer appeared, and his answers to his sister's criticisms were sometimes almost at random.

"Dicky, I'm not at all sure that I'm liking you this morning," she observed finally, looking across at him with a critically questioning smile. "A certain amount of non-responsiveness to my advances I can put up with -- from a brother -- but this morning you are positively inattentive. Tell me your troubles at once. Has Harris been bothering you, or did you lose a lot of money last night?"