Sherlock Holmes, the Galtonian!

In the late 1800s, in England, Darwinism and its intellectual cousin, genetic determinism, were the hot topics.  And Darwin's literal cousin, Francis Galton, was riding high, too.  He was read by the intelligentsia and his ideas both reflected, and seeped into, daily thinking about life.

The Sherlock Holmes story "The Adventures of the Reigate Squires", was published in 1893, and in it we see a reflection of those times, in the view of the role of inheritance that was then common (and still rides rampant for some today).  On a murder case, our sleuth was examining the paper shown here, which was a written note that was vital to solving the crime:



In his perceptive diagnosis of the writing on the note, Sherlock noticed that alternate words were written in different hands, that is, by two different people. The way the t's and e's were written gave that away.  In the story, this implicated two brothers, because the note was written to tie them together to their crime by each brother writing part of the note.

So what?  To Holmes, there was a profound reason he could connect the brothers, not just two different conspirators writing one note, to the crime.  As he said:

"There is a further point, however, which is subtler and of greater interest. There is something in common between these hands. They belong to men who are blood-relatives. It may be most obvious to you in the Greek e's, but to me there are many small points which indicate the same thing. I have no doubt at all that a family mannerism can be traced in these two specimens of writing. I am only, of course, giving you the leading results now of my examination of the paper. There were twenty-three other deductions which would be of more interest to experts than to you. They all tend to deepen the impression upon my mind that the Cunninghams, father and son, had written this letter.

In 1893, Mendel had not been rediscovered, so there were no genetics, and Darwin's nebulous 'gemmules' were basically quantitative determinants of traits.  But using such concepts at least implicitly, Francis Galton had been writing much about inheritance and family resemblance at that time, including behavioral traits such as intelligence, and one can presume that Conan Doyle, a physician by training, would have known about that work. At least, years later and in regard to fingerprints in a later Holmes story, the two were in at least some correspondence (see: http://publicdomainreview.org/2016/02/24/the-anthropometric-detective-and-his-racial-clues/ ).  Galton coined the word eugenics in 1883, ten years before the above Holmes story, an idea he advanced, in the spirit of viewing human traits as inherent, and thus amenable to improvement: preferential breeding to proliferate the positive, and the opposite to remove the negative, traits from the human  population.

Art imitates life....