Air may gain entrance into the pleural cavity as a result of perforating wounds of the chest, or of perforation through the diaphragm or the esophagus or the lung. The last-named event commonly occurs in consequence of disease of the lung or the pleura, but rarely it is due to rupture of air-vesicles from overdistention or from succussion, as in coughing, sneezing, laughing, and the like. Even under such conditions, however, it is probable that there must have been a weak point in the lung, perhaps the seat of emphysema or a pleural adhesion.
A remarkable instance of this sort is reported by Dr. B. Stiller,1 who was called urgently to see a young man whom he had previously treated for a mild attack of nervous dyspepsia. The patient was found in great distress, in a semirecumbent posture, and it was learned that he had been seized suddenly an