132 CLINICAL DIAGNOSTICS 



in consequence of great swelling or plugging of the larger 

 bronchi: severe bronchitis. 



3. If the exchange of gases in the lungs 

 is impaired: emphysema, beginning hepatization, and a 

 partial compression of the lungs by pleuritic exudate. 



Absence of the vesicular murmur, and no other sounds 

 present in the lung [i. e., total absence of any pulmonary 

 sound] occurs: 



1. If pleural exudates or tumors have displaced the lung 

 tissue : 



2. Rarely in severe vesicular pulmonary emphysema, or a 

 complete occlusion of a bronchus preventing access of air into 

 a certain portion of the lung. 



Jerking, interrupted respiratory sounds are often produced 

 by animals voluntarily, from restlessness or fear. In such 

 cases it is heard in both lungs. Pathologically it is 

 confined to certain portion of a lung, 

 and .is observed when the free entrance of air into the vesicles 

 is made difficult by a contraction or occlusion of the bronchi 

 (bronchitis). 



b. Bronchial tones. The bronchial respiratory sound 

 is normal in the larynx and trachea and, if the patient is 

 dyspneic, at the root of the lung. 



The occurrence of bronchial sounds in 

 the chest is always a sign of disease. It is 

 audible only when the bronchi are free and the vesicles contain 

 no air. 



Bronchial sounds displace the vesicular : 



1. If the vesicles are filled with exudate, therefore in all 

 pneumonias, especially in contagious pleuropneumonia of the 

 horse and in contagious pleuropneumonia of the ox. To be 

 heard, however, the hepatized portion of the lung must be of 

 the size of a clenched fist and lie next to the costal wall. 



2. If the lungs are compressed by pleuritic exudate 

 (atelectasis). The compression must be complete, for if the 



