Auscultation. 195 



at once when the mucus is expelled by coughing. Sometimes it 

 is modified by an occasional clicking sound from the flapping of 

 a shred of semi-solid mucus attached to the walls of a bronchial 

 tube. This disappears when breathing becomes more hurried. 



The sibilant (whistUng) r^le often acknowledges the same 

 causes as the sonorous, but indicates a narrower closure of the 

 tubes. More frequently it is heard further back on the chest and 

 results from pulmonary emphysema and dilatation of the smaller 

 bronchial tubes (broken wind, heaves). It is then heard chiefly 

 in expiration and coincidently with the second quick lifting of the 

 flank. It is further associated with the double lifting of the 

 flank in expiration, with the short, weak, paroxysmal cough and 

 the indigestion characteristic of broken wind. If the whistling 

 noise is so loud as to be heard without applying the ear to the 

 chest it is called wheezing. 



A mucous rdle is caused by air passing through any liquid 

 contained in the bronchial tubes, such as mucus, pus, or blood. It 

 may be imitated by blowing a large number of soap bubbles in a 

 thick lather and noticing them burst simultaneously or succes- 

 sively. It is chiefly observed in bronchitis after the preliminary dry 

 stage of the mucous membrane has passed off and an abundance of 

 mucus has been secreted. The nature of the sound will vary ac- 

 cording as it comes from the larger or the smaller tubes or in other 

 words as to whether the bubbles are large or small. That from 

 the smaller tubes is sometimes called a submucous rile. Either 

 of these riles may be temporary or permanent as the mucus may 

 be momentarily cleared away by coughing. 



The crepitant rile is a sound of very fine crackling which has 

 been variously compared to the crackling of salt when put on red 

 hot coals, the noise of a sponge expanding in water and the rub- 

 bing of a small lock of hair between the finger and thumb close to 

 the ear. The existence of the crepitant rAle usually denotes the 

 existence of the early stage of inflammation of the lungs, and the 

 progress of hepatization in such cases maybe traced by the advance 

 of the line of crepitation which precedes it. So the progressive ab- 

 sorption of exuded matter in recovery may be equally followed by 

 a circular line of crepitation gradually decreasing in area until it 

 meets in a point. The observations will be corroborated by the 

 dull sound elicited on percussing the parts. The production of 



