Here's something Britain's Secret Intelligence Service — also known as the MI6 of James Bond fame — probably doesn't want you to know. Frankly, we don't know if we wanted to know, either. Apparently, a fellow named Cummings found a certain bodily fluid could double as invisible ink. Guess which fluid!
You really can't make this stuff up sometimes. The man? Mansfield Cumming, the first chief of the SIS. The time? 1915, during the first World War. The invisible ink? Semen.
The then-deputy head of military intelligence at GHQ France, Walter Kirke, wrote in his diary that "C," or Cummings, was "making enquiries for invisible inks at the London University."
From the Telegraph:
he noted that he "heard from C that the best invisible ink is semen", which did not react to the main methods of detection. Furthermore it had the advantage of being readily available.
A member of staff close to "C", Frank Stagg, said that he would never forget his bosses' delight when his staff had found out that "semen would not react to iodine vapour".
Stagg noted that "we thought we had solved a great problem".
However, the discovery also led to some further problems, with the agent who had identified the novel use having to be moved from his department after becoming the butt of jokes.
"Readily available," huh? I guess with all those dapper British spies running aground of bodacious Russian operatives, MI6 could have been on to something. It's apparently just one of the many insights that'll be in an upcoming book titled MI6: The History of the Secret Intelligence Service 1909-1949 by Keith Jeffery, who was allowed to rummage through the SIS archives.