LONDON — If Sherlock Holmes was such a smart detective, why was he not put on the case of Jack the Ripper? It’s a reasonable question. After all, Sherlock made his first appearance in 1887 and the Ripper’s killing rampage took place between August and November 1888. With all other sleuths failing to catch the beast, why not call in the world’s greatest forensic mind?

Of course, you could protest that Sherlock did not really exist and the Ripper did. But Sir Arthur Conan Doyle, the mind behind Sherlock, was real enough and he—like his creation—inhabited the feverish world of late Victorian London. He would have followed the series of eviscerating murders in the sulfurous alleys of East London as they were reported in the press.

This thought began to trouble me as I immersed myself in the truly Holmesian world created at the Museum of London, at a show called “Sherlock Holmes, The Man Who Never Lived and Who Will Never Die.” To be honest, the visit did not begin well. The entrance to the show is a wall lined with books that conceals a secret door. It took several attempts for me to find the door and gain admission—a performance regarded with some contempt by the people behind me.