In "The Man That Corrupted Hadleyburg," Twain presents honesty as the primary virtue of Hadleyburg's citizens. As the story progresses, a motif emerges that presents this honesty in terms of the contrast between its strength as the town's reputation and its fragility as an actual trait in its citizens. This motif is established through a number of metaphors, the first of which occurs in the opening paragraph of Section 1:
Also, throughout the formative years temptations were kept out of the way of the young people, so that their honesty could have every chance to harden and solidify and become a part of their very bone.
In this passage, Twain treats honesty as a metaphorical component of the very bones of the Hadleyburg citizens—a strong, defining trait, but liable to effect the citizens to their very core when it is threatened or revealed to be weak.
This weakness is made gradually apparent throughout the rest of the story. Later in Section 1, when Mary Richards reveals her thoughts on the town to her husband, Edward, she uses the metaphorical language of a petrified and rotten substance (such as bone or fossil):
God knows I never had shade nor shadow of a doubt of my petrified and indestructible honesty until now—and now, under this very first big and real temptation, I—Edward, it is my belief that this town’s honesty is as rotten as mine is; as rotten as yours is.
While Twain paints this “petrified” or calcified honesty as a great strength in the beginning of the story, a strength that has grown over time like a bone, Mary's speech emphasizes instead its incredible, inevitable fragility.
The Hadleyburg citizens' honesty is supposedly the source of their virtue, but, as Mary suggests, the citizens' pride in their honesty is little more than proof of their extreme vanity—a vanity that will be an existential risk to the town.