Artificial pneumothorax is a surgical treatment to collapse the lung by inserting air or nitrogen into the pleural space. This was a treatment for tuberculosis in the lungs, known as pulmonary tuberculosis. The theory behind the treatment was that the lung needed to rest if the organ was to recover. Collapsing the lung gave it this rest. The medical world disagreed as to when was the best time to administer the treatment, if at all. Artificial pneumothorax treatments were replaced by antibiotics in the early 1940s.