Keen interest was aroused throughout the medical profession in the pulmonary pathology and symptomatology produced by the sojourn of aspirated foreign bodies in the lung by the publications of Chevalier Jackson, Willis F. Manges and Thomas McCrae. Jackson's description of his bronchoscopic observation of the mechanics of the type of obstruction producing the "asthmatoid wheeze," obstructive emphysema and obstructive atelectasis, correlated with the roentgenologic observations of Manges and the physical signs of McCrae, gave a new conception of the part played in pulmonary disease by impairment of ventilation and drainage through the tracheobronchial tree. The result of the work has been a clinical and experimental revision of knowledge of many of the pulmonary diseases. This is especially true in pulmonary atelectasis. All physical signs, symptoms and roentgen observations of foreign body obstruction may be produced by pulmonary dysfunction and disease. The asthmatoid wheeze, obstructive emphysema and obstructive atelectasis may be