DIGESTIVE APPARATUS. 135 



e. Pleuritic friction sounds. Normally the pulmonary 

 pleura plays noiselessly upon the costal pleura during the 

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

 become rough and dry from inflammatory deposits upon them, 

 a sound is produced at respiration. This sound is best heard 

 where the movement of the pleural laminae is greatest, there- 

 fore near the sharp borders of the lung. The intensity of pleu- 

 ritic friction sounds depends upon the extent of the disease 

 [pleuritis]. They are audible as grazing or rubbing sounds 

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

 is emitted in a series of jerking, creaking, 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 ox. It rarely 

 occurs from the presence of tumors or neoformations 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 

 expiration, may sometimes even be felt, and occur most fre- 

 quently in a series of abrupt, jerking noises upon which cough 

 has no influence. Rales are commonly more pronounce 1 

 at inspiration than at expiration, are not jerking in character, 

 and are removed or modified by cough. 



Diseases of the Respiratory Apparatus. 



a. Cavities of the Head. 



Nasal Hemorrhage (Epistaxis.). Bleeding from the vessels 

 of the cavities of the head. Generally unilateral. Blood appears 

 in drops or in a thin stream and is not foamy. 



Acute ncsal catarrh. Rhinitis catarrhosa. Congestion of the 

 mucous membranes, serous or mucous, rarely mucopurulent nasal 

 discharge. Only when disease is severe is mild fever present; 

 transient swelling of the submaxillary lymph glands. 



Chronic nasal catarrh. Mostly unilateral. Discharge often 

 mucopurulent or light colored and "glassy" in appearance; quan- 



