Identifying errors in the Sherlock Holmes corpus is a well-established fan activity. Arthur Conan Doyle read widely to find obscure information that Holmes was likely to know and use in his investigations. Holmes himself was portrayed as widely read, and he is fond of quoting both classics and popular works of the day.
In The Sign of Four, the Andaman Islands in the Bay of Bengal play a prominent role, both as the place of origin of the character Tonga, an indigenous Andaman person, and for its role as a British penal colony where Major Morstan and Major Sholto had been stationed and Jonathan Small had done time. While the bare-bones description of the islands themselves, which Dr. Watson finds in a newly published gazeteer, are accurate, the description of the indigenous people (“aborigines”) is both inaccurate and, as many modern critics have noted, extremely racist.
They are naturally hideous, having large, misshapen heads, small, fierce eyes, and distorted features.
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