The gall bladder is given to Mars in the western scheme, and the reasoning is humoral: the organ stores the bile, and yellow bile is the choleric humour of the four-humour scheme inherited from Hippocrates and Galen, hot and dry, associated with anger, quickness and a lean and vigorous constitution, and Mars is the hot and dry planet. The vocabulary survives in English in the words choler, bilious and gall used of temper. In the Chinese scheme the gall bladder, dan, is the fu paired with the liver, belongs to the wood phase, and is associated not with anger but with decisiveness and courage; a person lacking resolve is said to have a small gall bladder, and the idiom is still current. Two unrelated traditions thus attached the same organ to boldness by entirely different reasoning.
Ayurveda assigns the gall bladder's bile to Pachaka Pitta, the digestive fire seated chiefly in the stomach and small intestine that Sushruta Samhita and Charaka Samhita treat as the body's central transformative heat, closer in function to the West's four humours than to a single organ's output. A specific piece of documented history belongs to the gall bladder rather than the liver: cholecystectomy, the surgical removal of the organ, was first performed in 1882 by the German surgeon Carl Langenbuch, who argued, correctly, that the gall bladder was not essential to life, a claim that had to overcome real medical resistance at the time.
Sources Christian AstrologyWilliam Lilly with The Roots of Ayurveda: Selections from Sanskrit Medical WritingsDominik Wujastyk