Back in the day before the internet, military intelligence was a totally different ball game.
Before any government was concerned with Wikileaks, a diary entry from WWI Britain reveals that the UK’s Secret Intelligence Service (MI6) suggested that the “that the best invisible ink is semen.” Spunk-based invisible transmissions were praised by SIS chief (I am not making this up) Mansfield Cumming, for their ability to evade traditional methods of detection and because the fluid is “readily available.” (But not if you haven’t gotten off yet, ladies, am I right?)
The Telegraph describes the practice, sadly leaving out the method of collecting the substance.
A member of staff close to “C”, Frank Stagg, said that he would never forget his bosses’ delight when the Deputy Chief Censor said one day that one of his staff had found out that “semen would not react to iodine vapour”.
Stagg noted that “we thought we had solved a great problem”.
Of course, it wasn’t all fun and jacking off during World War I in the semen-based message sending brigade. The agent who first decided to put pen and ejaculate to paper eventually had to be moved from his post due to the unbearable teasing, and the protocol apparently had to be revised when it was discovered that not using freshly-acquired love juice caused transmissions to have an “unusual smell.”