A Judoon cataloguing a human. (TV: Smith and Jones)
Cataloguing was a process that was once used by Judoon law enforcement to identify different species, such as separating humans from non-humans.
History
This process was used by Judoon who were trying to locate a criminal, Florence Finnegan, a plasmavore who could mimic human biology, who was hiding among humans in the Royal Hope Hospital on Earth, which the Judoon transported to the Moon via a H₂O scoop. The Judoon scanned each lifeform's head, marking the humans who had already been scanned with a black "X" on the back of their hand.
Martha Jones showed traces of non-Human DNA (that of the Doctor) which caused the Judoon to do a "full scan." When she was proved to be human, she was given some sort of voucher for "compensation." (TV: Smith and Jones)
