Carl Linnaeus, the father of biological taxonomy, also had a hand in inventing this tool for categorizing anything. An Object Lesson.
… _In 1767, near the end of his career, Linnaeus began to use “little paper slips of a standard size” to record information about plants and animals. According to the historians Isabelle Charmantier and Staffan Müller-Wille, these paper slips offered “an expedient solution to an information-overload crisis” for the Swedish scientist. More than 1,000 of them, measuring five by three inches, are housed at London’s Linnean Society. Each contains notes about plants and material culled from books and other publications. While flimsier than heavy stock and cut by hand, they’re virtually indistinguishable from modern index cards. …