Without the midi-chlorians, life could not exist, and we would have no knowledge of the Force. They continually speak to us, telling us the will of the Force. When you learn to quiet your mind, you'll hear them speaking to you.
—Anonymous Jedi master romanticizing the mundane nature of midi-chlorians
Midi-chlorians were microscopic parasites. Nourished by the Force, they were known to take up residence within the cells of carbon-based organisms, where they would feed on raw Force energy directly from the source. Midi-chlorian counts were linked to potential in the Force, ranging from normal Human levels of 2,500 per cell to the much higher levels of Force-sensitives. Midi-chlorian counts were measured through a blood test; the larger Jedi Orders along with the Inquisitorius used this method to locate Force-sensitive children before and after the Great Jedi Purge.
Studies of midi-chlorians occurred among those who could master the Force and those who could not. Medical teams and Jedi healers had both worked to understand the relationship between midi-chlorians and the Force, and had come to the conclusion early that they were mere Force parasites; contrary to the musings and teachings of certain spiritual groups and leaders, midi-chlorians were neither the source nor the conduit to the Force.
Though midi-chlorians were generally considered unremarkable — proving neither beneficial nor detrimental to their hosts — Hego Damask, the Dark Master of the Order of the Sith Lords, discovered a way to manipulate midi-chlorians to alter life. Utilizing this esoteric method, he was able to sicken and kill the most virile beings, heal and invigorate the terminally ill, or even bestow Force-sensitivity onto non-sensitives.
Midi-chloroxian[]
Midi-chloroxians, silicon-based analogues to the midi-chlorians, were also known to exist. Just as midi-chlorians resided within the cells of carbon-based organisms to feed on their Force energy, so did the midi-chloroxians reside within the cells of silicon-based lifeforms for the same purpose. Due to the dearth of silicon-based life in the Known Galaxy, however, midi-chloroxians were not as abundant as their carbon-based counterparts.
Exogorths and mynocks were known host species to the midi-chloroxians.