In Chapter 2 of How the Other Half Lives, Riis discusses how the tenement house system reached its current sordid state. Through the use of simile, Riis describes the spread of this unwholesome and predatory system:
It is one curse of the tenement house system that the worst houses exercise a levelling influence upon all the rest, just as one bad boy in a school room will spoil the whole class.
In the above passage, Riis uses simile to compare the particularly bad tenement houses to naughty school boys, capable of corroding the surrounding environment when left to their own devices. While this passage does not directly accuse the residents of the tenement house system for this corruption, it does imply that behavior—specifically, human misbehavior—can spread like a disease. This seems directed more against the tenants' criminal behavior as opposed to that of their landlords.
It is worth noting that similar rhetoric is often used to stigmatize immigrants, with some asserting that immigration should be curtailed to prevent malicious actors from entering and causing trouble. While Riis clearly uses this rhetoric in the hopes of improving the lives of underprivileged tenement residents, stating that one "bad boy" will poison the entire batch is a generalization with dangerous implications.
At the beginning of Chapter 14, Riis attempts to differentiate between flats—or standard apartments—and tenement housing, outlining specific features that distinguish tenements as uniquely unlivable spaces. He notes that an absence of privacy is the feature that best characterizes tenement life, with halls that are "highway[s] for all the world." To further emphasize this point, Riis delves into simile:
Below Houston Street the door-bell in our age is as extinct as the dodo [. . .]. Skilled and well-paid labor puts its stamp on the tenement even in spite of the open door, and usually soon supplies the missing bell.
In an attempt to showcase just how rare true privacy or personal space is in the tenements, Riis compares the tenement doorbell to a dodo—a bird widely known to be extinct by the end of the 19th century. Here, Riis establishes for his readership that privacy is a privilege of the middle and upper classes. As he later notes, a rise in skilled or well-paid laborers in the tenements would lead to an increased proliferation of doorbells, and the privacy that accompanies them. Security, privacy, comfort, safety—all these and more are privileges that those with money can afford and of which those in the tenements are deprived.
In Chapter 14, Riis details the plight of those in the slums he considers innocent victims of their environment: namely, women and young girls. In doing so, he utilizes a simile that doubles as a biblical allusion:
And yet it is not an uncommon thing to find sweet and innocent girls, singularly untouched by the evil around them, true wives and faithful mothers, literally "like jewels in a swine's snout," in the worst of the infamous barracks.
Riis uses this simile to compare young, innocent girls to jewels that must suffer the "swine's snout" of the tenement. The simile, which Riis includes as a quote, comes from Proverbs 11:22: "As a jewel of gold in a swine's snout, so is a fair woman which is without discretion." This simile, taken from a biblical context and employed by Riis to further his argument, implies that the primary evil these women and girls face is the corruption of their innocence: specifically, their sexual discretion. Riis himself notes later in this very same segment that "inherent purity revolts from the naked brutality of vice as seen in slums." This passage utilizes a common—and rather misogynistic—tactic for generating moral outrage: implying the incipient corruption of female virtue and innocence.