518 AUSCULTATION. 



Abnormal sounds consist either in modifications of the 

 normal respiratory sounds, or in superadded sounds entirely 

 distinct in their nature. 



The vesicular sound may be increased in pitch, it may be 

 diminished, or it may be entirely wanting. 



When the respiratory murmur is more intense than natural, 

 this intensity is said to be general when heard over the entire 

 surface of the thoracic walls, and partial when heard only over 

 a portion of that surface. The intensity may be such as to 

 simulate juvenile respiration, or it may have some rudeness, like 

 the respiratory sound heard normally behind the superior 

 part of the shoulder extended to other parts of the chest. A 

 general increase in the respiratory murmur results from any 

 cause which accelerates respiration. Thus it results from 

 active exercise, or from the high fever which accompanies 

 the majority of acute maladies. The increase of the respira- 

 tory murmur in one lung alone, or in different parts of one 

 or both lungs, invariably depends on some obstruction to the 

 entrance of air into some other portion of the respiratory 

 apparatus. Such obstruction may, however, be very varied, 

 so that this symptom may be looked upon as of very secondary 

 importance in diagnosis. Among the obstacles to the entrance 

 of air may be noticed bronchitis, with thickened walls and 

 diminished calibre of the tubes, the blocking up of one or 

 more tubes by mucus, hepatisation of a portion of lung, 

 pulmonary oedema, phthisis pulmonalis, hydrothorax, and 

 pneumothorax. Coincident symptoms may decide whether 

 any, or which, of these causes exist in a particular case. In 

 these cases of partial increase in the respiratory murmur, 

 the origin of the condition has suggested the very appropriate 

 name of supplementary respiration. The occurrence of the 

 rude vesicular sound in other parts of the chest than is 

 natural, commonly depends on some condensation of pul- 



