112 DISEASES OF THE BESPIBATOBY ROANS. 



sound) may be heard in the normal respiration of the pharynx, 

 windpipe, and the anterior part of the chest in diseased conditions ; 

 it appears where any part of the lung is deprived of air, and the 

 disease has plugge.l up the smaller bronchia and extended to the 

 larger-sized bronchia. This is the case in the various pulmonic 

 affections, where we find large sections of the lungs are obstructed, 

 or in compression of the lung by a pleuritic exudate or by tumors, 

 and in rare cases by the pressure of the diaphragm where it is 

 pushed forward from the collections of fluids in the abdomen. It 

 is also heard when a quantity of mucus is coming up the bronchial 

 tubes; this sound disappears when the mucus is coughed up. 

 Lastly, we find it in cases where the lung has large cavernous 

 spaces in it. 



Indistinct respiratory bruits are heard in lobular pneumonia, 

 where the diseased lobules are located among clear tissue that the 

 air is passing into, and where the true character of the respiratory 

 bruit is not heard on account of the loud rattling of the air going 

 through the contracted bronchial tubes. Indistinct respiratory 

 sounds are also heard where there is more or less mucus in the 

 bronchial tubes and after the animal has had a coughing spell the 

 true bronchial sound is heard. 



Irregular bronchial sounds (rattling bruits) are caused by the 

 movement of the mucus or fluids that are in the air-passages, 

 being carried to and fro by the passage of air. They ai'e dry 

 (snoring, wheezing) where a small quantity of sticky mucus 

 collects in the bronchial tubes, as is seen in some catarrhal affec- 

 tions, and in cases where the mucous membrane is considerably 

 swollen. The snoring sound is generally heard in the large bron- 

 chial tubes. The wheezing sounds occur in the smaller bronchial 

 tubes. A spell of coughing produces considerable change in the 

 ■character of the slight, rattling sounds of the chest. The rattling 

 sounds are moist when the secretions are liquid; the thicker they 

 are the duller the bruits become. AVe hear moist, rattling sounds 

 when the secretions are collected in the large bronchia; this sound 

 is also heard when there are cavernous portions in the lungs. We 

 find much less when this is the case in the middle bronchia, and a 

 very low bronchial bruit when the small bronchia are involved. 

 By this means we can distinguish in what position the irritation lies 

 in the bronchia; this is rather important in diagnosing a case of 



