THE EXAMINATION" OF A SICK HOESE. 19 



mothorax, there is an excess of air in the chest cavity, the percussion 

 sound becomes abnormally loud and clear. 



Auscultation consists in the examination of the lungs with the ear 

 applied closely to the chest wall. As the air goes in and out of the 

 lungs a certain soft sound is made which can be heard distinctly, 

 especially upon inspiration. This sound is intensified by anything 

 that accelerates the rate of respiration, such as exercise. This soft, 

 rustling sound is known as vesicular murmur, and wherever it is 

 heard it signifies that the lung contains air and is functionally active. 

 The vesicular murmur is weakened when there is an infiammatory 

 infiltration of the lung tissue or when the lungs are compressed by 

 fluid in the chest cavity. The vesicular murmur disappears when air 

 is excluded by the accumulation of inflammatory product, as in pneu- 

 monia, and when the lungs are compressed by fluid in the chest 

 cavity. The vesicular murmur becomes rough and harsh in the early 

 stages of inflammation of the lungs, and this is often the first sign of 

 the beginning of pneumonia. 



By applying the ear over the lower part of the windpipe in front of 

 the breastbone a somewhat harsh, blowing sound may be heard. This 

 is known as the bronchial murmur and is heard in normal conditions 

 near the lower part of the trachea and to a limited extent in the ante- 

 rior portions of the lungs after sharp exercise. When the bronchial 

 murmur is heard over other portions of the lungs, it may signify that 

 the lungs are more or less solidified by disease and the blowing bron- 

 chial murmur is transmitted through this solid lung to the ear from a 

 distant part of the chest. The bronchial murmur in an abnormal 

 place signifies that there exists pneumonia or that the lungs are com- 

 pressed by fluid in the chest cavity. 



Additional sounds are heard in the lungs in some diseased condi- 

 tions. For example, when fluid collects in the air passages and the 

 air is forced through it or is caused to pass through tubes containing 

 secretions or pus. Such sounds are of a gurgling or bubbling nature 

 and are known as mucous rales. Mucous rales are spoken of as being 

 large or small as they are distinct or indistinct, depending upon the 

 quantity of fluid that is present and the size of the tube in which this 

 sound is produced. Mucous rales occur in pneumonia after the solid- 

 ified parts begin to break down at the end of the disease. They occur 

 in bronchitis and in tuberculosis, where there is an excess of secretion. 



Sometimes a shrill sound is heard, like the note of a whistle, fife, or 

 flute. This is due to a dry constriction of the bronchial tubes and it 

 is heard in chronic bronchitis and in tuberculosis. 



A friction sound is heard in pleurisy. This is due to the rubbing 

 together of roughened surfaces, and the sound produced is similar 

 to a dry rubbing sound that is caused by rubbing the hands together 

 or by rubbing upon each other two dry, rough pieces of leather. 



