Sentence:  So complete was this illusion, claims Lott, that many audience members, including Mark Twain's mother, believed they were seeing authentic, biologically black performers on New York stages. Of course, <WSD>wench</WSD> characters seem to especially test the bounds of authentic performance. [...] Extant photographs and engravings of <WSD>wench</WSD> performers do not always represent them as blacked up, [...] In antebellum minstrel shows, <WSD>wench</WSD> songs were most often sung "about" mulatto women rather than by them. 
Meaning of the word marked with <WSD> tags:  A black woman (of any age), especially if in a condition of servitude.