128 CLINICAL DIAGNOSTICS. 



■exudative (early) stage, and last stag-e (resolution) of fibrin- 

 ous pneumonia (contagious pleuropneumonia of the horse). 



2. Dry rales appear if a email quantity of a tough 

 bronchial secretion is present, or if- the mucous membrane is 

 greatly swollen. These conditions produce stenosis of the 

 bronchi, hence the sound is stenotic and of a sonorous, luim- 

 Diiiiij;, hissin!^, squeaky. zcJiisili)!^:^, (sibilant) character. Dry 

 rales most commonly attend chronic diseases : chronic bron- 

 chitis, compression of the bronchi by nodules (tuberculosis, 

 chronic pneumonia) and tumors (echinoccocci). In the 

 echinococcus disease of the ox the rale has a peculiar (quurk- 

 send) character. 



A wheezing, crackling, whistling or piping, rale-lik? 

 sound is heard in interstitial emphysema of the lungs. It is 

 most pronounced during expiration. 



e. Pleuritic friction sounds. Normally the pulmon- 

 ary pleura plays noiselessly upon the costal pleura during th.e 

 movements of^each respiratory act. If, however, the pleurae 

 become rough and dry from inflammatory deposits upon the:r.. 

 a sound is produced at respiration. This sound is best hear 1 

 where the movement of the pleural laminae is greatest. t!ie:e- 

 fore near the sharp borders of the lung. The intensity of pl'rr.- 

 ritic friction sounds depends upon the extent of the di2eas2 

 [pleuritis]. They are audible as o-ra:::iiig or ruhbiug sou::cL 

 just below the ear ; if there is an intimate adhesion the sound 

 is emitted in a series of jcrkiii'^, ci'cakiiii^, or crackling noises. 



A pleuritic friction sound appears in 

 dry or fibrinous pleuritis only. It is most 

 frequently heard in contagious pleuropneumonia of the horse 

 and in contagious pleuropneumonia of the c-c. It rarely 

 occurs from the presence of tumors or neoformni^n: upon the 

 pleura. In tuberculosis, as a rule, no fric- 

 tion sound is heard. 



Pleuritic friction sounds are easily confused with rales. 

 Friction sounds are heard regularly at inspiration and 



