LESSON XXV 

 THE CIRCULATION (Concluded) 



THE CHARACTER AND VELOCITY OF THE ARTERIAL AND VENOUS 

 PULSATIONS. POLYGRAPHY 



1. The Application of the Sphygmograph. Determine the rate of 

 the subject's heart by palpation of the radial pulse. How is the rate 

 affected by the act of swallowing? 



Study the construction of the sphygmograph. It usually consists 

 of a vibrating rod which acts in magnified form upon a recording lever. 

 The end of the rod is equipped with an oval projection which is adjusted 

 over the artery. Apply this instrument securely to the radial artery 

 and record a number of normal sphygmographic curves. Study their 

 character. 



FIG. 83. THE DUDGEON SPHYGMOGRAPH IN POSITION. (Howett.) 



Ask the subject to close his mouth and nostrils with the fingers of 

 the free hand and exhale forcibly. Explain the result (Valsalva's 

 experiment). 



2. Relation Between the Arterial Pulse and the Action of the Heart. 

 Obtain a sphygmographic record of the radial pulse in proper relation 

 with a record of the apex-beat registered by means of a cardiograph. 

 Note whether any extrasy stoles are present. 



Allow a cardiograph and a sphygmograph (radial artery) to register 

 their excursions in the same ordinate upon a rapidly rotating drum, 

 above the record of a tuning-fork. Obtain the approximate distance 

 between the ascending aorta and the radial artery, and ascertain the 

 speed of the pulse-wave by computing the difference of the cardiac and 

 radial impulses. 



3. The Use of the Phlebograph. Apply a metal .or glass cup to 

 the jugular fossa and connect it with a recording tambour. Also register 



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