Pecquet discovered the thoracic duct in dogs and its relation to the lacteals. Using a dog that was digesting, he described the thoracic duct, its entry into the subclavian veins, and the receptaculum chyli or chyle reservoir. The chyle reservoir had been sought after since Aselli’s discovery of the chyliferous vessels (lacteals) in the dog. English translation, London, 1653.