Unknown word in a too knowable language

At

https://repository.duke.edu/dc/eaa/B0319

and

https://repository.duke.edu/dc/eaa/B0320

you’ll find a pair of documents from 1857 Charleston. They advertise slaves for sale. https://en.wikipedia.org/wiki/Old_Slave_Mart

In each, a woman named Eve is referred to with the term prolap. In 1857, readers of those advertisements must have known what that word meant, but I don’t know now. It isn’t in the Oxford English Dictionary, the Dictionary of American Regional English, or any of the nineteenth-century dictionaries that I’ve consulted, and a Newspapers.com search through the 1850s yields only an unrelated medical term, prolapse. I didn’t find it, either, in any of the several 1850s gynecology texts that I found at Archive.org. So today I submitted prolap to the OED.

I was being sentimental. I intended to make myself believe that I was completing Eve’s forgotten name and nobly getting it admitted to a dictionary’s kind of memory. But both the dictionary’s language and what memory does with it will tell me I’m no nobleman. All that my memory and my words actually did was to dress me up as a headwaiter, station me with a volume of the OED behind a reservation desk, and let me admit the gentlemen and ladies already in the corpus to the privilege of being known there once again. The grammar of my notion about Eve was possessive, as if she were an Eve of my own to decide about in a future of my own. But long before I was born, the orders concerning Eve had already been written into the book I wielded, and the whiteness of the shirt that I wore when I read them out had always been a part of their language.

Alexandria Gazette (Alexandria, Virginia), October 10, 1853, page 3. In the nineteenth century the word “mechanic” referred to any blue-collar worker, as in Whitman’s “the mechanic’s wife with her babe at her nipple interceding for every person born” (Song of Myself, sec. 41).