RESPIRATORY APPARATUS. 133 



vesicles contain air at all a feeble vesicular murmur can still 

 be heard. 



A special variety of bronchial respir- 

 ation is the amphoric respiration, which is a bruit like the 

 sound produced by gently blowing across the mouth of a 

 narrow-necked bottle. In animals it is rare, but appears if 

 large caverns in the lung communicate with bronchi (pulmon- 

 ary gangrene). On percussion, in place of the 

 dulled sound which is usual when the 

 respiration is bronchial, a tympanitic 

 tone or a cracked-pot resonance is heard. 



That bronchial respiration may become audible in bronchi 

 must not be occluded ; if they are filled with masses of exu- 

 date, no respiratory sound is heard. A forcible cough, how- 

 ever, may dislodge and eject the exudate and the bronchi 

 become free again. 



C. The vague or indefinite respiratory sounds. Such 

 sounds are spoken of when it can not be determined whether 

 they belong to the vesicular or bronchial respiration. Vague 

 respiration is heard if hepatization is setting in, the vesicular 

 murmur becoming weak and the bronchial sound just begin- 

 ning. A slight compression of the lungs or partial occlusion 

 of the bronchi with exudate may also produce it. 



d. Rales or rhonchi. Rales are heard in disease and 

 appear if the bronchi or a cavern in the lung contain movable 

 exudate against which air is forced. 



1. Moist rales appear if the bronchi contain a 

 quantity of light, fluid exudation (bronchitis). The larger the 

 bronchi and the greater the quantity of exudate they contain, 

 the larger will be the b u b b 1 c s and the coarser the rales. 

 In the large bronchi and in caverns, the rales may assume a 

 gurgling or bubbling character. We also distinguish medium, 

 coarse, and fine rales ; the latter originating in the bronchioli. 



Rales may occur irregularly and are not always of like 

 intensity. Faint rales are heard only at inspiration, increas- 



