Well written story. I'm tempted to shelf this as horror but I wouldn't because I use that shelf only if there is some supernatural element. I can't say that the ending is surprising but it's very disturbing.
The Mammoth Book of Victorian and Edwardian Ghost Stories
Charles Dickens, Henry James, Robert Hugh Benson, Tom Gallon, Clive Pemberton, Allen Upward, Alice Perrin, Lettice Galbraith, J.E.P. Muddock, Theo Gift, Frank Cowper, J.B. Harwood, Grant Allen, Alexandre Chatrian, Émile Erckmann, Erckmann-Chatrian, Rhoda Broughton, Dinah