396 THE MECHANICS OF THE CIRCULATION, HEMODYNAMICS 



the blood entering it is always returned into the vascular system by way of its 

 distal cannula, the volume of the circulating blood must remain the same. All 

 in all, it seems fair to state that the objections which may be raised against the 

 use of this instrument (Starling) are in no way more valid than those raised 

 against the employment of manometers or physiological apparatus of a similar 

 kind.i 



Bii 



ii X'-.. /v^ iii ••/' .J 



FiQ. 208. — Diagram of Recordino Stromuhr. 

 C, cylinder; K, piston; F, piston-rod; AR and AR, tubes for influx of blood; A» 

 double U-shaped valve connected with blood-vessel at B and B'; D\ and Di, positions 

 occupied by valve when blood is directed either into the left or right side of the cylinder; 

 Ro, Sf, H and St, apparatus required for registering the excursions of the piston upon 

 the paper of the kymograph. 



An idea regarding the volume of the blood flow may be obtained from the 

 accompanying table which embraces the results of a series of experiments made 

 by Burton-Opitz^ and Tschuewsky.' The values here given are calculated for 

 a dog weighing about 15 kg. : 



^ An optical stromuhr has been described by Hiirthle in Pfliiger's Archiv, 

 cxlvii, 1912, 509. 



2 Pfliiger's Archiv, cxxix, 1909, 189, and Quart. Jour, of Exp. Physiol., vii, 

 1913, 57. 



»Ibid.,xcvii, 1903, 214. 



