100 CLINICAL DIAGNOSTICS. 



A yawn is a long-drawn-out, deep inspiration taken with 

 the mouth held wide open. The inspiratory muscles assist in 

 producing it. 



Pathological Sounds (stridores). When the respiratory 

 apparatus is diseased the following pathological 

 sounds may occur : 



1. The wheezing or blowing sound which is stenotic in 

 its character, emanates from the nasal cavities. It is more 

 pronounced at inspiration, and results from a narrowing 

 of the nasal chambers due to the presence of tumors, 

 swelling of the alae of the nostrils, septum or chonchae, en- 

 largements of the turbinated bones or fractures of these bones, 

 fractures of the nasal bones, or deposits of exudate on the 

 mucous membrane. Depending upon the condition of the 

 mucous membrane, the stenotic sound may be accompanied 

 by either moist or dry rattling noises. 



2. "The Mucous Click" (klatschender Nasalton) is a 

 peculiar metallic, short expiratory sound first described by 

 DieckerhofL It occurs during an inspiratory-expiratory dys- 

 pnea if the nasal mucous membrane is very moist. At a 

 forced inspiration that part of the nasal mucous membrane 

 which unites vith the skin of the false nostril, is sucked 

 against the opposite wall to which it adheres for a moment ; 

 when an expiration takes place this adhesion is broken, caus- 

 ing a metallic '"slapping" tone to be emitted. This sound is 

 of no significance. 



3. Sneezing is an explosive expiration through the nose, 

 which originates reflexly from irritations to the nasal mucous 

 membrane. It is heard in rhinitis (nasal catarrh) or when 

 foreign bodies enter the nasal cavities. Sneezing only occurs 

 in the dog, cat, and fowl. 



4. Snoring takes place when the act of breathing is ef- 

 fected through the open mouth, the soft palate undergoing a 

 fluttering motion. In swine and dogs it occurs when the 

 lumen or the nasal cavities is contracted by swelling or thick- 



