18. A little later in the evening Dr. Touchon's efforts to entertain us appeared to slacken. You know what I mean; a gentle hint. When a sensitive person perceives it he says instinctively: "Well, I must be going"; and that was in fact what Mme. Storey said. Our host made only perfunctory attempts to detain us. Finally he said:
"I'll ride home with you in the cab."
"That will be nice," said my mistress.
Ordinarily she would have protested against such a thing and it was this which first gave me the idea that something was in the wind.
When we retired into the little pink boudoir for our wraps she said softly: "Bella, he is meditating another murder."
"Oh, good heavens!" I said, turning faint. "Is it us?"
"No, silly," she said with an indulgent smile. "Think it out. Follow this symbol
