In P.G. Wodehouse's "Summer Lightning," the narrative features a keen observation of a butler's expression. This look symbolizes a conflict of loyalty, as it reflects the butler's internal struggle when he has yielded to temptation, going against his better instincts. The moment reveals the complexities of human nature, particularly in situations where duty and personal interests collide.

The phrase suggests that an expert in reading facial expressions, or physiognomy, would recognize this telltale sign of guilt and complicity in unethical behavior. It emphasizes the butler's role in the deception of his employer regarding the theft, highlighting themes of betrayal and moral quandaries within domestic settings.