The panoply of elderly individuals in the Sherlock Holmes stories is impressive: Mr. Frankland, the old crank in The Hound of the Baskervilles, the miserly Josiah Amberley in "The Retired Colourman," Old Mr. Farquhar, the previous owner of Watson's practice.
But there were many others, some of whom go almost unnoticed. What similarities do we see among them? How did Conan Doyle's writing about them change over time? It's just a Trifle.