THE BLOODFLOW IN THE ARTERIES 



201 



which is connected at its outer end with a manometer and prolonged 

 inside the horizontal tube, where they are bent at opposite right angles, 

 so that the inner end of one of them the proximal tube points up 



D 



Fig. 57. 



Fig. 58. 



Fig. 57. Diagram to show principle of Pilot's tubes for measuring velocity pulse. In both 

 tubes the fluid will rise because of lateral pressure, but in the proximal (left-hand) tube it will 

 rise higher than in the distal, because it will also be affected by the velocity of flow. 



Fig. 58. Diagram to illustrate the principle of Cybulski's Photo-hematotachometer. The fluid 

 in C stands higher than that in D in proportion to the velocity of flow of the blood along 



Fig. 59. Dudgeon's sphygmograph. (From Jackson.) 



stream, and records not only the lateral pressure but also the pressure 

 produced by the sudden increase in velocity of the flow, while the 



