Chap, iv.] THE VASCULAR MECHANISM. 



205 



instrument) that the pressure in the ventricle is for the time 



t T- » t 



being above that in the aorta. 



D 



TUXTX. 



AMI 



X 



Fig. 51. Simultaneous Curves of Aortic and Ventricular Pressure and 

 of the Differential Manometer. Hurthle. 



A°. aorta. V. ventricle. D. differential manometer, x — x, the base line in each 

 respectively. The recording surface is travelling slowly, the time marker t, t mark- 

 ing seconds. 



1 2 



3 4 



1 



3 4 



3 4 



Fig. 52. The same. 



3 4 



The recording surface is travelling quickly ; the vibrations of the tuning-fork t, 

 t, are 100 (double vibrations) a second. 



An examination of the figures shews that the pressures in the 

 ventricle and the aorta become equal at the mark (1). Before 

 this though the pressure in the ventricle is rising rapidly that in 

 the aorta is not rising, indeed is continuing to sink ; the closed 



