THE CIRCULATION 



105 



resting upon the mercury in the distal limb of the manometer, is set at zero. In 

 order to be able to retain this line during the succeeding experiments, adjust the sta- 



FIG. 66. SCHEMA TO SHOW THE CONNECTION MADE BETWEEN THE ARTERY AND MAN- 

 OMETER. 



M, Manometer; H, mercurial column; F, float; D, recording needle; K, kymograph; 

 B, tube leading to reservoir filled with solution of sodium carbonate; R, rubber tubing 

 filled with sodium carbonate solution; C, glass cannula in artery; A, clip upon artery; 

 V, maximal-minimal valve (Frank) to be inserted in tluVcircuit; 1, maximal, 2, minimal 

 side; Vi, maximal valve of Hurthle. A minimal valve is obtained by inverting the central 

 tube. 



FIG. 67. DIAGRAM TO SHOW THE ADJUSTMENTS NECESSARY FOR DETERMINING THE 



ZERO-LINE OF THE MANOMETER (M). 



Its central limb (A) is brought upon the same horizontal line as the level of the water in 

 the glass bulb (B) when held at the level of the blood-vessel (C). 



tionary recording lever of the manometer to the level of the writing needle of the 

 float. The latter may then rise above this zero-line to indicate the blood-pressure. 



