172 Veterinary Medicine. 



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 breatlj^ng becomes more hurried. 



The sibilant (whistling) rdle 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 coiucidently 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 rtle is cau,sed 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 successive- 

 ly. 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 r^le. Either 

 of these r^les may be temporary or permanent as the mucus may 

 be momentarily cleared away by coughing. 



The crepitant r^le 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 rdle usually denotes the 

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

 progress of hepatization in such cases may be traced by the ad- 

 vance of the line of crepitation which precedes it. So the progres- 

 sive absorption of exuded matter in recovery may be equally fol- 

 lowed by a line of crepitation gradually decreasing in area until it 

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

 dull sound elicited on percussing the parts. The production of 



