130 CLINICAL DIAGNOSTICS. 



sound is not so flat, because the solidification of the lung is 

 not complete, the morbid process appearing in the form of 

 more or less isolated centers or foci which are not entirely 

 void of air. In hypostatic, metastatic, and ichorus pneumo- 

 nias, swine plague, dog distemper, verminous pneumonia and 

 tuberculosis the percussion sound is not diffusely dulled, but 

 a dull sound is emitted over the dense diseased centers only, 

 b. Chronic interstitial pneumonia com- 

 bined with atelectasis. 



2. If tumors or neoformations are pres- 

 ent in the lungs : glanders, tuberculosis, carcinoma, sarcoma, 

 echinococci, etc. 



3. If an airless, solid medium comes be- 

 tween the lung and the pleximeter as in i 



Inflammatory swelling of the thoracic wall (after mus- 

 tard applications) ; neoformations on the pleura; collections of 

 considerable fluid exudate or transudate in the chest; pleuro- 

 pneumonia of the horse, contagious pleuropneumonia of the 

 ox, and in swine plague. In the horse the presence of but a 

 few litres of fluid in the chest cannot usually be determined. 



Pleuritic dullness is characterized by its horizontal upper 

 boundary which shifts if the position of the body is changed, 

 the contained fluid seeking the lowest level. This latter is 

 most marked in small animals. 



X. Auscultation of the Lungs. 



During breathing, when the air enters the lung and causes 

 it to move, sounds are produced. The occurrence and charac- 

 ter of these sounds furnish important data in regard to the 

 condition of the air passages and of the surface of the lung. 

 The intensity of the sounds varies with the depth of the res- 

 pirations; when the breathing is forced they are augmented. 

 Therefore, to make them more audible it is sometimes advisa- 

 ble to exercise the patient before auscultating. The sounds 



