CHAPTER IX.* 



POLYSPHYGMOGRAPH TRACINGS. 



These experiments consist in obtaining graphic records of the 

 pulses of the radial and carotid arteries, of the apex beat and of the 

 venous pulse in the jugular vein.f 



The experiments are important not only because the results 

 if properly interpreted throw much light on the cardio-vascular 

 mechanism, but because of the value of the technique in clinical 

 diagnosis. The tracings are often difficult to obtain, and great 

 care and patience must be exercised in adjusting the various re- 

 ceiving tambours. This is especially so for the radial pulse and 

 apex beat. When these two cannot be satisfactorily obtained to- 

 gether, the carotid should be substituted for the radial. The ob- 

 served person must remove his shirt and lie on a couch or table. 

 Sometimes it is best to lie on the side, sometimes on the back. 

 While cardiac tracings are being taken, the breath should be held 

 for a few moments. 



Experiment 38. 



A. The Velocity of Transmission of the Pulse Wave. (Pro- 

 pagation of Pulse Wave). With the arm easily extended and 

 resting on the arm support, apply the button of the receiving tam- 

 bour over the radial artery and adjust the pressure until a maximal 

 movement of the recording lever is observed. Taking care that the 

 radial tambour does not slip, now apply the carotid tambour by 

 hand (apply opposite the angle of the jaw). When a maximal 

 pulsation of both of the levers is obtained, adjust the writing points 

 to a slowly moving clockwork drum. The writing points should be 

 as nearly as possible in the same perpendicular, and should be 



*For the experiments of this chapter two sessions of three or four hours each 

 are necessary. 



fNotes and tracings of these experiments are to be taken by every member 

 of the class. 



93 



