394 EESPIRATION. 



familiar. Snoring is an idiosyncrasy with many individuals, 

 though those who do not snore habitually may do so when 

 the system is unusually exhausted and relaxed. It only oc- 

 curs when the mouth is open, and the sound is produced by 

 a vibration, and sort of flapping, of the velum pendulum pa- 

 lati between the two currents of air from the mouth and 

 nose, together with a vibration in the column of air itself. 



The auscultatory phenomena which accompany the act of 

 respiration have been made the subject of special experimen- 

 tal observations by Dr. Flint, who, from carefully recorded 

 examinations of a large number of healthy persons, has ar- 

 rived at the following conclusions : 1 



Applying the stethoscope over the larynx or trachea, a 

 sound is heard, of a distinctly and purely tubular character, 

 accompanying both acts of respiration. In inspiration, " it 

 attains its maximum of intensity quickly after the develop- 

 ment of the sound, and maintains the same intensity to the 

 close of the act, when the sound abruptly ends, as if sudden- 

 ly cut off." After a brief interval, the sound of expiration 

 follows. This is also tubular in quality ; it soon attains its 

 maximum of intensity, but, unlike the sound of inspiration, 

 gradually dies away and is lost imperceptibly. It is seen 

 that these phenomena correspond with the nature of the two 

 acts of respiration. 



Sounds approximating in character to the foregoing are 

 heard over the bronchial tubes before they penetrate the 

 lungs. 



Over the substance of the lungs, a sound may be heard 

 entirely different in its character from that heard over the 

 larynx, trachea, or bronchial tubes. In inspiration, the sound 

 is much less intense than over the trachea, and has a breezy, 

 expansive, or what is called in auscultation a vesicular char- 

 acter. It is much lower in pitch than the tracheal sound. It 



1 FLINT, Physical Exploration and Diagnosis of Diseases affecting tlw Respi- 

 ratory Organs, Philadelphia, 1856, p. 137 et seq. We give but a brief summary 

 of these results, which are specially applied to auscultation iu disease. 



