It’s from the Arthur Conan Doyle stories. One of those little details original-flavor Holmes fans like to pull out and use. ^_^ In “Adventure of the Greek Interpreter,” Holmes tells Watson that his grandmother was the sister of “the French artist, Vernet.”
I think that’s also the story where he tells Watson that his family are rural gentry.
from Tumblr http://ift.tt/1dAe9PX