In today’s rewriting, I discovered that I was apparently fine with having two characters use the word “nonetheless” in the space of two lines. The word has since been taken out and shot.
I also did a touch of research and discovered to my relief that forensic pathologists in 1928 could detect morphine. If that had turned out to be wrong, it would have meant some substantial tone shifts for the next few chapters, as the police would have gone from one step ahead to two steps behind. Workable, but tricky.