* Dr. Manges has developed such a high degree of skill in the fluoroscopic diagnosis of non-opaque foreign bodies by the obstructive emphysema they produce that he has located peanut kernels and other vegetable substances with absolute accuracy and unfailing certainty in dozens of cases at the Bronchoscopic Clinic. [FIG. 74--Expiratory valve-like bronchial obstruction by non-radiopaque foreign body, producing an acute obstructive emphysema. Peanut kernel in right main bronchus. Note (a) depression of right diaphragm; (b) displacement of heart and mediastinum to left; (c) greater transparency of the invaded side. Ray-plate made by Willis F. Manges.] _Complete bronchial obstruction_ shows a density over the whole area the aeration and drainage of which has been cut off (Fig. 75). Pulmonary abscess formation and "drowned lung" (accumulated secretion in the bronchi and bronchioli) are shown by the definite shadows produced (Fig. 76). [140] Dense and metallic objects will usually be readily seen in the roentgenograms and fluoroscope, but many foreign bodies are of a nature which will produce no shadow; the roentgenologist should, therefore, be prepared to interpret the pulmonary pathology, and should not dismiss the case as negative for foreign body because one is not seen. Even metallic objects are in rare cases exceedingly difficult to demonstrate. [FIG. 75.--Radiograph showing pathology resulting from complete obstruction of a bronchus with atelectasis and drowned lung resulting. Foot of an alarm clock in left bronchus of 4 year old child. Present 25 days. Plate made by Johnston and Grier.] _Positive Films of the Tracheo-bronchial Tree as an Aid to Localization_.--In order to localize the bronchus invaded by a small foreign body the positive film is laid over the negative of the patient showing the foreign body. The shadow of the foreign body will then show through the overlying positive film. These positive films are made in twelve sizes, and the size selected should be that corresponding to the size of the patient as shown by the roentgenograph. The dome of the diaphragm and the dome of the pleura are taken as visceral landmarks for placing the positive films which have lines indicating these levels. If the shadow of the foreign body be faint it may be strengthened by an ink mark on the uncoated side of the plate. [FIG. 76.--Partial bronchial obstruction for long period of time Pathology, bronchiectasis and pulmonary abscess, produced by the presence for 4 years of a nail in the left lung of a boy of 10 years] _Bronchial mapping_ is readily accomplished by the author's method of endobronchial insufflation of a roentgenopaque inert powder such as bismuth subnitrate or subcarbonate (Fig. 77). The roentgenopaque substance may be injected in a fluid mixture if preferred, but the walls are better outlined with the powder (Fig. 77).