The multiple inconsistencies in the 60 Sherlock Holmes adventures have kept Sherlockians material to ponder and argue over for more than a century.
Less noticed is the remarkable consistency of the tales, given that they were written over a period of exactly 40 years and held in little regard by their author.
In Memories and Adventures, Sir Arthur Conan Doyle writes: “To make a real character, one must sacrifice everything to consistency and remember Goldsmith’s criticism of Johnson that ‘he would make the little fishes talk like whales.’” ACD says this of Watson, but it applies to Holmes as well.
Holmes makes his famous comment that “when you have eliminated the impossible, whatever remains – however improbable – must be the truth” not only in The Sign of Four but also in three other stories. That doesn’t even count A Study in Scarlet, where he employs the same technique and calls it “the method of exclusion.”
Also in A Study in Scarlet, the debut adventure, Holmes remarks, “It is a capital mistake to theorize before one has data.” He goes on to say something similar not just once or twice but in six other stories.
Recently, I came across a much less obvious example of Holmes uttering variations of a sleuthing maxim across several different stories.
“It is of the highest important in the art of detection to be able to recognize, out of a number of facts, which are incidental and which are vital,” Holmes says in “The Reigate Squires.”
In “The Naval Treaty,” he complains of too much evidence making that difficult. “What was vital was overlaid and hidden by what was irrelevant.”
And in “The Adventure of the Priory School,” there’s this: “Before we start to investigate that, let us try to realize what we do know, so as to make the most of it and to separate the essential from the accidental.”
Dr. Watson may be a little fuzzy on whether he was shot in the shoulder or the leg, but over four decades he gives us a remarkably consistent portrait of Holmes the sleuth-hound.