Content Warning: This section discusses a pandemic and death. The source text includes ableist and racist language, which this guide reproduces only in quotations. 

The color scarlet is a motif principally due to the color that humans turned after contracting the plague—a bright shade of red that gave the plague its official name, the “Scarlet Death.” Since the plague was invariably fatal, scarlet thus symbolizes the inevitability of death and, more generally, imminent societal collapse, illustrating the theme of The Impermanence of Humanity in the Face of Nature’s Power. 

The word “scarlet” also becomes a focal point in the generational clash between Smith and his grandchildren, who object to their grandfather’s use of this “fancy” term and substitute the simpler “red” instead. This illustrates The Cyclical Nature of History and Civilization, as the culture that Smith embodies has all but died out.

Throughout the book, “savage” functions as a motif related to the social changes caused by the plague. London describes one of the grandchildren as “savage-looking,” and Smith takes every opportunity to decry the children as “savages”; he remarks, for example, “You are true savages” (36), after the children dig up a human skeleton for its teeth.