For nearly a century and a half, the rigors of composing short detective fiction—as with the composition of fiction of any sort—have remained essentially the same:
The short story form has inherent limitations for the writer of detective fiction, but in the most capable hands these can be turned to triumphant effect, with consequent pleasures for the reader that the detective novel, for all its enticements, cannot provide. The establishing of a credible and engaging narrative voice is essential to a successful crime short; flamboyance of invention and a certain leisureliness in the telling must co-exist with economy of style, compression, and a well-paced plot; character must be sketched out swiftly but decisively; every incident must carry its share of relevance to the main idea, which itself needs to be simple and surprising. The art of the short detective story continues to evolve; but all its essential qualities and characteristics were developed in the course of the nineteenth century, particularly in its last two decades. — Michael Cox, Introduction to Victorian Tales of Mystery and Detection (1992)
Cox adds:
In this anthology, all the stories are mysteries, but not all are detective stories, either because they lack the central figure of the detective or because no formal process of investigation, deduction, and revelation takes place. But all the stories, in whichever category the purist prefers to place them, are branches of the same tree—the protean genre known in the nineteenth century as sensation fiction, a form of popular literature which, in another of Julian Symons’s happy encapsulations, “has produced a few masterpieces, many good books, and an enormous mass of more or less entertaining rubbish.”
Either because of—or in spite of—Cox’s invoking of Symons, you might want to buy the book, sometimes known as Victorian Detective Stories.
And don’t miss Doug Greene’s fine anthology of mysteries from the same era, Detection by Gaslight.