THE CIRCULATION. 31 1 



heart being pulled toward the apex during ventricular systole, thus 

 dilating the cavity of the auricle and producing an aspiration on the 

 venous flow. The arrest of this aspiration when the auricle is full 

 of blood at the end of the ventricular systole stops the flow of blood 

 in the veins and thus a wave is produced. 



Fredericque and Delchef believe the second wave is not the beat- 



Fig. 103 a. Schema of the Normal Jugular Pulse (P. </.). 

 ( FRANCOIS-FRANCK. ) 



1, Curve of ascent due to auricular systole, a, Curve of descent which com- 

 mences at the diastole of the auricle and continues during the ventricular 

 diastole, VD, notwithstanding the two small elevations 2 and 3, one of which 

 is produced by the sudden tension of the ventricular muscle at the moment of 

 systole, VS, with the elevation of the tricuspid valve. The wave 2 marks the 

 beginning of ventricular systole, wave 3 the end of ventricular systole. 4, 

 Swelling of the vein due to the gradual filling of the venous system. PC, 

 Cardiac pulsation. 



ing of the carotid as held by Mackenzie, but is due to closure of the 

 tricuspid valve. 



Morrow of Montreal, makes six waves in. the venous pulse tracing 

 which may be named either from their supposed cause or from their 

 time relations to the cardiac cycle, as follows : 



1. The auricular or presystolic wave. 



2. The ventricular or systolic wave. 



3. The auricular or systolic collapse. 



4. The first onflow or prediastolic wave. 



