RESPIRATORY APPARATUS. 101 



ening of the mucous membrane. Snoring is also noted in the 

 ox when the retro-pharyngeal lymph glands are swollen or 

 enlarged ; further in the course of parturient paresis. Horses 

 under chloroform sometimes snore. 



5. Rattling is a stenotic laryngeal sound which occurs 

 when the vocal cords are relaxed. It is heard in severe in- 

 flammations of the larynx or of the neighboring pharyngeal 

 mucous membrane ; phlegmon of the pharynx and edema of 

 the glottis. 



6. The most important pathological re- 

 spiratory tone is the stenotic laryngeal tone. Normally 

 the sound emitted by the larynx is a soft stenotic sound audi- 

 ble when the ear is placed over the organ. [It can be imitated 

 by pronouncing the German "ch"]. If the lumen cf the lar- 

 ynx is narrowed, the noise becomes loud. It is most fre- 

 quently heard in the horse, and is one of the characteristic 

 symptoms of roaring. 



Ordinarily the tone is emitted when the respirations are 

 increased during exercise, but in cases where the lumen of 

 the larynx is much diminished, it may appear when the patient 

 is at rest. 



The character of the tone will vary from whistling to a 

 pronounced hoarse or roaring sound. 



Besides it may be due to a firm swelling of the laryngeal 

 mucous membrane (phlegmonous laryngitis, strangles), tu- 

 mors in the larynx or its neighborhood which prevent the 

 free entrance of air. 



7. Loud rattling noises [garglings] are heard when the 

 larynx or the trachea contains loose masses of mucus. 



8. Groaning (moaning, grunting) is heard when a long 

 inspiration is followed by a prolonged, audible expiration 

 through a partially closed glottis. The sound is emitted only 

 at expiration. Groaning is not necessarily a sign of disease, 

 for it often occurs in healthy animals, especially cattle after 

 a full feed or when pregnant. Groaning is produced by the 



