Name a Canonical character who seems to have taught Sherlock Holmes something that he used to solve a later case . . . .
Surely, Holmes came to his detective career complete, one might think. He seemed so on top of it when Watson first met him. And yet, it only makes sense that Sherlock Holmes, who took so much from so many fields to form his bag of work-tools, who add a few things as he went along.
Got the answer yet? If you do, you were ahead of me on this, until tonight.
Looking over The Sign of the Four, pondering a question on a certain other test of Sherlockian knowledge, I ran across Thaddeus Sholto's explanation of what a clever fellow is brother Bartholomew is.
"How do you think he found out where the treasure was? He had come to the conclusion that it was somewhere indoors: so he worked out all the cubic space of the house, and made measurements everywhere, so that not one inch should be unaccounted for." A lot of detailed explanation later, we learn Bartholomew found four feet in the house that was unaccounted for.
Just like the six feet of hallway that Sherlock Holmes found unaccounted for in "The Norwood Builder." As he tells Watson in A Study in Scarlet, "There is a strong family resemblance about misdeeds, and if you have all the details of a thousand at your finger ends, it is odd if you can't unravel the thousand and first."
And in "The Norwood Builder" we see that in action. Finding a man hidden in a house works on the same basic principle as finding a good-sized treasure in a house, and Sherlock Holmes was not the sort of man to let Bartholomew Sholto's cleverness go un-noted, especially after his untimely demise before Holmes could even make his acquaintance.
So the next time you want to celebrate "Norwood Builder," remember to tip your cap to the late Bartholomew Sholto, the guy who basically solved it first.