Sentence:  Mr. Martin could not imagine life without niggers, and since they were inevitable, he considered it a matter of common expedience to know what to expect of them. Hence, he had developed his own science of <WSD>niggerology</WSD>, which he used like an Etruscan bed, lopping off some here, stretching some there to achieve a common fit for all. 
Meaning of the word marked with <WSD> tags:  The study of black people, especially when isolated as a problem group.