In the second chapter of A Study in Scarlet, Holmes claims to have discovered a test for hemoglobin that will be important in solving crimes. However his test would be worthless, since it would not tell human blood from animal blood, nor could it tell that the blood was not that of the alleged criminal.Elementary, my dear Sherlock.

I played Sherlock Holmes once. On night duty at the morgue
at the Santo Tomas former pistol range, a body was brought in. The body of an Army major, lying on the stretcher face down, with at least six .45 bullet wounds in his back.
The Japs had no .45 ammo, and such a tight group could not have been produced by a single assailant firing consecutive rounds because the tremendous kinetic energy of a .45 slug would have propelled the body forward, giving a linear group. He had been shot from behind by several men at same instant. Probably by some of his own men. To the rear stretcher bearer I said sotto voce:"What did he do wrong?"
"Took all of the Canadian bacon out of the C Rations for himself."

Gluttony really was a mortal sin in this case!

Nothing could save his bacon.

Was he afried of dying, or did he treat it as a simple matter of fat?

After all there was nowt he could do about it.
I'll sign off now before I'm accused of hamming it up.