THE HEART 97 



third fingers of your right hand upon the radial artery close to the wrist. It is then 

 a simple matter to determine the frequency of the pulse. Besides, the third finger 

 may be employed to compress the artery and the second to palpate. In this way the 

 experimenter may obtain an idea regarding the tension prevailing in the vascular 

 system of the subject. 



4. The Heart Sounds. Adjust your ear directly to the area of the 

 apex-beat of the subject. Study the quality and intensity of the car- 

 diac sounds. How many sounds do you hear? Note the pause fol- 

 lowing the second sound. Palpate the radial pulse and determine 

 whether these sounds are produced during ventricular systole or diastole. 

 Ascertain precisely when they occur and where they are most intense. 

 Request the subject to stop respiring after a deep inspiration and 

 observe the lesser audibility of these sounds. State the reason for this 

 change. Ask the subject to cease respiring after a forced expiration. 

 Why are these sounds now more clearly heard? 



Repeat these tests with the help of a stethoscope. Place its chest- 

 piece over different regions of the heart. Compare the relative in- 

 tensity of the sounds when heard at the apex and when heard over the 

 junction of the second right costal cartilage. Do you obtain a dif- 

 ference? Give reasons for it. 



Having thoroughly familiarized yourself with the character of the 

 normal heart sounds, study a simple murmur, such as may arise in con- 

 sequence of mitral stenosis or aortic regurgitation. Note its char- 

 acter, point of greatest intensity, and relation to the carcliac cycle. 

 Also familiarize yourself with the so-called extracardiac friction sounds, 

 hemic murmurs, and arterial and venous bruits. 



