Arnold,
I failed to mention that I was referring to your link in my earlier post.
The Sugden book, last updated in 1995, was an attempt to debunk some of the myths generated by the Jack the Ripper industry, especially by the flood of “centennial” publications in 1988. He argues that, while the suggestion that the police used this technique has been touted around by “ripperologists” (I hate that word) since the 1960s, there is no evidence to support it—no surviving photos, no formal police records of the technique being applied, nor even any reliable, contemporaneous newspaper reports.