RESPIRATORY APPARATUS. 127' 



sounds are spoken of when it can not be determined whether 

 they belong to the vesicular or bronchial respiration. A'ague 

 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 bubbles 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 tine rales ; the latter originating in the bronchioli. 



Rales may occur irregularly and are not always of like 

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

 ing in intensity as the inspiration progresses; coughing may 

 temporarily, remove them. The intensity of rales depends upon 

 the extent of the disease and the topographical position of the 

 diseased part. 



Moist rales originate from the to-and-fro movement of 

 mucus [pus, blood, liquid exudate], the forming and bursting- 

 of bubbles, and the vibrations produced by these acts. Accord- 

 ing to whether rales attend vesicular, bronchial or amphoric' 

 respiration their tone will vary ; metallic rales as a rule accom- 

 pany bronchial respiration. 



By crepitant rales: we understand very fine, crackling 

 noises, which resemble the sound heard when the ear is rested 

 very lightly upon the haired skin of an animal. Taking their 

 origin into consideration they can be grouped with neither the 

 moist nor the dry rales. They originate from a separation, at 

 inspiration, of the adhering walls of the bronchi and vesicles. 

 They appear in Irrcr.chioHt::,, pulmonary edema and in the 



