[FIG. 77.--Roentgenogram showing the author's method of bronchial mapping or lung-mapping by the bronchoscopic introduction of opaque substances (in this instance powdered bismuth subnitrate) into the lung of the patient. Plate made by David R. Bowen. (Illustration, strengthened for reproduction, is from author's article in American Journal of Roentgenology, Oct., 1918.)] ERRORS TO AVOID IN SUSPECTED FOREIGN BODY CASES 1. Do not reach for the foreign body with the fingers, lest the foreign body be thereby pushed into the larynx, or the larynx be thus traumatized. 2. Do not hold up the patient by the heels, lest a tracheally lodged foreign body be dislodged and asphyxiate the patient by becoming jammed in the glottis. [143] 3. Do not fail to have a roentgenogram made, if possible, whether the foreign body in question is of a kind dense to the ray or not. 4. Do not fail to search endoscopically for a foreign body in all cases of doubt. 5. Do not pass blindly an esophageal bougie, probang, or other instrument. 6. Do not tell the patient he has no foreign body until after roentgenray examination, physical examination, indirect examination, and endoscopy have all proven negative. SUMMARY SYMPTOMATOLOGY AND DIAGNOSIS OF FOREIGN BODIES IN THE AIR AND FOOD PASSAGES _Initial symptoms_ are choking, gagging, coughing, and wheezing, often followed by a symptomless interval. The foreign body may be in the larynx, trachea, bronchi, nasal chambers, nasopharynx, fauces, tonsil, pharynx, hypopharynx, esophagus, stomach, intestinal canal, or may have been passed by bowel, coughed out or spat out, with or without the knowledge of the patient. Initial choking, etcetera may have escaped notice, or may have been forgotten.