Just re-reading the first Sherlock story, "A Study in Scarlet" (first published by Ward Lock in 1887), prompted to do so by the new, third series of "Sherlock" on BBC1. "The Sign of Four" was wittily alluded to in the second episode at Watson's wedding. Sherlock had deduced, before the doctor, that Mary was pregnant and vowed to be always there for "all three of you, sorry, both of you, miscounted!"
To return to the first story, in chapter three Sherlock asks Inspector Gregson if he has read the Van Jansen case of '34. "Read it up - you really should. There's nothing new under the sun. It has all been done before."
Often true in matters of language change, too, Holmes. Or, at least, most changes have been around longer than I first appreciate, as you showed me yesterday with your "very unique". And luckily there's always someone who can put me right - now through a science-fiction device called the iPad.