246 PATHOLOGICAL RESPIRATORY SOUNDS. 



cases vesicular sounds disappear, and the condensed or solidified lung-tissue conducts 

 the tubular sound of the large bronchi to the surface of the chest. It also occurs 

 in large cavities, with resistant walls near the surface of the lung, provided these 

 cavities communicate with a large bronchus. 



(2.) The amphoric sound is compared to that produced by blowing over the 

 mouth of an empty bottle. It occurs either when a cavity at least the size of 

 the fist exists in the lung, which is so blown into during respiration that a 

 peculiar amphoric-like sound with a metallic timbre is produced; or when the 

 lung still contains air, and is capable of expansion; as there is still air in the 

 pleural cavity, it acts as a resonator, and causes an amphoric sound, simultaneous 

 with the change of air in the lungs. 



(3.) If obstruction occurs in the course of the air-passages of the lungs, various 

 results may accrue, according to the nature of the resistance: (a.) owing to various 

 causes, e.g., in the apices of the lungs there may be partial swelling of the walls 

 of the air-tubes, or infiltration into the air-cells which hinders the regular supply of 

 air. In these cases, parts of the lung are not supplied with air continuously ; it 

 only reaches them periodically. In these cases a cog-wheel sound occurs. A 

 similar sound may be heard occasionally in a normal lung, when the muscles of 

 the chest contract in a periodic spasmodic manner. (6. ) When the air entering 

 large bronchi causes the formation of bubbles in the mucus which may have 

 accumulated there, "mucous rales" are produced. They also occur in small 

 spaces when the walls are separated from their fluid contents by the air entering 

 during inspiration, or when the walls, being adherent to each other, are suddenly 

 pulled asunder. The rales are distinguished as moist (when the contents are 

 fluid), or as dry (when the contents are sticky); they may be inspiratory, 

 expiratory, or continuous, or they may be coarse or fine; further, there is the 

 very fine crepitation or crackling sound, and lastly, the metallic tinkling caused 

 in large cavities through resonance, (c.) When the mucous membrane of the 

 bronchi is greatly swollen, or is so covered with mucus that the air must force its 

 way through, deep sonorous roncTii (ronchi sonori) may occur in the large air- 

 passages, and clear shrill sibillant sounds (ronchi sibilantes) in the smaller ones. 

 When there is extensive bronchial catarrh, not unfrequently we feel the chest- 

 wall vibrating with the rale sounds (Bronchial fremitus). 



(4. ) If fluid and air occur together in one pleural cavity in which the lung is 

 collapsed, on moving the person's thorax vigorously, we hear a sound such as is 

 produced when air and water are shaken together in a bottle. This is the 

 SUCCUSSION sound of Hippocrates. Much more rarely, this sound is heard under 

 similar conditions in large pulmonary cavities. 



(5.) When the two apposed surfaces of the pleura are inflamed, have become 

 soft, and are covered with exudation, they move over each other during 

 respiration, and in doing so, give rise to FRICTION sounds, which can be felt (often 

 by the patient himself), and can also be heard. The sound is comparable to the 

 sound produced by bending new leather. 



(6.) When we speak or sing in a loud tone, the walls of the chest vibrate 

 (PECTORAL FREMITUS), because the vibration of the vocal cords is propagated 

 throughout the entire bronchial ramifications. The vibration is, of course, 

 greatest near the trachea and large bronchi. If there be much exudation or air in 

 the pleura, or great accumulation of mucus in the bronchi, the pectoral fremitus 

 is diminished or altogether absent. 



All conditions which cause bronchial breathing increase the pectoral fremitus. 

 Under normal circumstances, therefore, it is louder where bronchial breathing 

 is heard normally. The ear hears an intensified sound, which is called BRONCHO- 

 PHONY. If through effusion into the pleura or inflammatory processes in the lung- 

 tissue the bronchi are pressed flat, a peculiar bleating sound (^EGOPHONY) may be 

 heard, 



