20 CHAPTER XXXIV. 



ON THE CIRCULATORY SYSTEM. 



Beat and sounds of the human heart. 



Feel the apex beat. Place the points of the fingers of your 

 hand upon the fifth intercostal space on the left of the sternum 

 arid feel the movements of the heart. 



Count the rate of pulsation in the minute by your 

 watch. 



Note the character of the impulse and its variations with 

 the respiration and the posture of the body sitting, standing, 

 and in the reclining position. Count the number to each 

 respiration. 



2. Listen to the*sounds of the heart with a stethoscope (binoral). 

 The phonendoscope is the best form of this instrument. It 

 consists of a heavy metal disc excavated upon one side, over 

 this a vulcanite diaphragm is fixed. Two rubber tubes are 

 attached to the other side by short metal tubes, and their 

 free ends by ear-pieces to each ear. One hand holds the 

 instrument. 



Seat yourself opposite the subject and hold the diaphragm 

 against the surface of the chest, a little to the sternal side of 

 the apex beat and clear of clothing, which must not be allowed 

 to rub against the instrument. 



Distinguish between the two sounds. The longer one corre- 

 . sponds to the ventricular systole, the sharp second sound to the 

 closure of the aortic and pulmonary valves. 



