Oof! Badly misattributes stuff in Dorothy L. Sayers, and of course I noticed. Claims that “an analytical chemist“ (Sir James Lubbock) finds “arsenic on the victim's shoe“ during The Unpleasantness of the Bellona Club. It's nothing of the kind: Wimsey goes to see him, Lubbock is finishing a previous job, and then says the bit Hone quotes about arsenic about *that*.
The sample from the shoe is paint, not arsenic.
Immediate eyebrow raising here.