<p>Critics have continually been baffled by Jack London’s contradictory representations of racial problems. Occasionally, he unabashedly exhibited his position as a white supremacist, but in some of his writings, he suddenly displayed heartful sympathy toward non-white races, especially those oppressed by Western imperial domination. The aim of this paper is to highlight his racial attitude, which was greatly influenced by his observation of the lepers he encountered in Hawaii during his round-the-world-cruise on the Snark.</p><p>Leprosy and its trope seem to have fascinated London, especially after his visit to Molokai; a place where Hawaiian lepers were segregated and treated by a US government medical facility. While London wrote many essays and stories about leprosy following this visit, my great interest in these texts lies in his contradictions about the disease. Following his visit to Molokai, his first reference to the disease was in an essay titled “The Lepers of Molokai,” in which he insisted “that the horrors of Molokai, as they have been painted in the past, do not exist.” However, his subsequent short stories about leprosy in Hawaii convey a contradictory statement: Molokai is portrayed as “the horror” that separates lepers from their families and confines them for life. This paper contends that this is not a result of a mindset change in London, but a symptom of inner conflict between his perception and the reality of the disease. Under the contemporary influence of Social Darwinism, he considered the white race as immune to leprosy because it had undergone natural selection to become the fittest. However, undeniable evidence of whites who had contracted leprosy haunted London so persistently, that he could not ignore the possibility of contracting the disease. Thus, he fought against the leprosy tropes that unnecessarily condemned the infected.</p><p>Following the Hawaiian experience, London became haunted by the possibility of contracting leprosy, which strongly influenced his writing. The Scarlet Plague was written shortly after he abandoned the cruise with the Snark, because he believed he had contracted what he at the time believed to be leprosy, but later turned out to be just psoriasis. This short novel describes the strong tropes from ancient times concerning leprosy as defective. The narrator, Professor Smith, who accepts those tropes without question, believing that the disease is meted out to lower-class people as a punishment for their immoral and violent behavior, but in truth, the disease attacks indiscriminately, disregarding class hierarchy. London perhaps knew about the indiscriminate nature of the disease very well; however, he could not escape from this widely accepted punitive trope. Thus, he inevitably retained the differentiation between a white and a non-white, or a dominant and a submissive person. This unresolved tension led to ambiguity and contradiction in his writings about race and disease.</p>