Midi-chlorian
this species of microscopic organism was known to the Jedi Knights as a symbiotic creature that exists within the cells of every living creature. Life in the galaxy was dependent upon the midi-chlorians, although the exact genesis of the microscopic midi-chlorians was unknown. There was no pattern which dictated the concentration of midi-chlorians in a being's make-up, but a higher count of midi-chlorians in a being's cells allowed them to touch the Force. As the count increased, so did the being's ability to contact and control the Force, but true mastery of the Force could only come from intense concentration and study. Thus, the Jedi Knights devoted themselves to the study and control of the Force, and developed techniques that could detect high concentrations of midi-chlorians in young infants. During the last years of the Old Republic, some Jedi began to believe that the relationship between midi-chlorians and the Force might actually be the opposite of traditional thinking. They believed that the Force created the midi-chlorians, as a way for it to reach out to life throughout the galaxy.