5S6 SPORADIC DISEASES. 



TPvACHEAL SOUNDS, 



Except at its entrance into the chest, the trachea yields no 

 sound. At this point, however, a blowing sound — tracheo-bron- 

 chial respiration — can be heard, more prolonged during the 

 expiratory act. In disease this may be increased. When the 

 bronchi contain much mucus or other fluid, a moist rattle — 

 mucous rale — may be heard, accompanied by a wheezing, 

 gurgling, or spumous or frothy sound. 



THORACIC SOUNDS, 



The thoracic sounds are divided into pulmonary, pleural, and 

 cardiac. The pulmonary sounds are of two kinds, namely, the 

 vesicular and the bronchial sounds. 



1. Vesicular, also called the respiratory murmur, is heard 

 during both inspiration and expiration. During the inspiratory 

 act it is a soft diffused murmur of a gentle breezy character : 

 slightly harsher and more hollow during expiration, and not 

 above one-fourth the length of that during inspiration. It is 

 caused by the entrance and expulsion of air to and from the 

 terminal portions of the bronchi and air sacs. The intensity of 

 this sound is increased with exercise or other causes of quickened 

 respiratory movements, as fever; is louder in chests thinly 

 clothed with flesh ; stronger in the young than in adults, hence, 

 when strong, it is called " puerile " ; it is also louder when the 

 stomach is empty. Puerile respiration depends upon the smaller 

 size of the air vesicles, and the greater elasticity of the lung 

 tissue ; in the very old the murmur is scarcely preceptible, and 

 is called " senile." Senile respiration may also result from slow 

 breathing, or any cause wdiich obstructs the entrance of air 

 into the lungs. If either modification is present to the same 

 extent in the same region of both sides of the chest, they 

 indicate no other condition than the natural ones above indi- 

 cated ; but if the murmur is j)uerile on one side and senile or 

 absent on the other, the first indicates a compensating action 

 of that lung, supplementary to diminished action in the other. 

 The vesicular murmur is best heard in the superior portion 

 of the lower third of the chest, from behind the elbow and 

 Blioulder to about the ninth rib, whence it diminishes iu force, 



